Search

In order to obtain a uniform and effectively toughened poly (lactic acid) film by blending with low content of poly (ethylene octene) (POE) with high elasticity, the tailored interfacial intermolecular interaction and entanglement between the two phases of the PLA/POE blend was innovatively constructed via the facile reactive melt blending process through the reaction of the epoxy/anhydride groups grafted on the POE chains with the end groups of PLA chains (PLA/GPOE-MPOE). It was observed that POE domains were embedded tightly in PLA matrix with a fuzzy interface and abundant interface transition area, and the impact fractured surface of the blend showed an obvious plastic deformation with less occurrence of fibrillation of PLA matrix or interfacial de-bonding. Compared with neat PLA and directly blended PLA/POE blends, the PLA/GPOE-MPOE blend exhibited much higher complex viscosity/storage modulus, much lower tanδ values in the terminal region, and obvious strain-hardening behavior. The deviation in viscoelastic behavior of PLA/GPOE-MPOE from linear PLA indicated the enhanced molecular entanglement between the long-branched chains, resulting in an enhancement of the stretching ability during biaxial drawing of the blend. Uniform PLA/GPOE-MPOE films with draw ratio as high as 7 × 7 were obtained through biaxial stretching, which showed much higher tensile strength and the elongation at break than that of neat PLA and PLA/POE film. This work provides a facile method for fabricating toughening PLA films with application potentials.

The structure-performance evolution of Co/N-AC catalyst during ethylene oligomerization was investigated in detail. It was found that the catalytic activity sharply decreased in the first 30 h with the ethylene conversion decreasing from 64 to 4%. Butene selectivity increased gradually in the first 10 h then remained about 74%, while the selectivity for hexene and octene exhibited an opposite trend. The ratio of α-olefin to isomers for butene increased greatly with time on stream and most of the generated butene was 1-butene. Based on the structure characterization at different reaction stages, CoOx was suggested to be major active phase and the coverage of long-chain hydrocarbons as well as the loss of surface CoOx active sites due to size growth of Co3O4 nanoparticles were the main reasons for catalytic deactivation. The structure-performance evolution of Co/N-AC catalyst during ethylene oligomerization was investigated and the coverage of long-chain hydrocarbons as well as the loss of surface CoOx active sites due to size growth of Co3O4 nanoparticles were the main reasons for catalytic deactivation

We report the kinetics of ethylene oligomerization over the Ni-H-Beta for temperatures ranging between 50 and 100 °C and pressures ranging between 5 and 28 atm. According to our results, the apparent activation energies involved in the formation of butene, hexene, and octene are 44, 78, and 60 kJ.mol−1, respectively. The measured lower apparent activation energy for butene formation relative to hexene and octene is a likely result of the fact that the measured butene formation is not the true (forward) rate of formation of butene but it the net rate because of the consumption of butene in secondary reactions. Analysis of the reaction order indicates that participation of butene in chain-growth reactions takes place via desorption followed by re-adsorption of butene on the catalyst. The results also indicate that hexene undergoes a similar process. In the present paper, we refer to the pathway involving co-oligomerization of butene and hexene as “cascade co-oligomerization”. Based on these findings, we proposed a reaction network and modeled reaction rate expressions for ethylene consumption and butene, hexene, and octene formation based on the construction of a micro-kinetic model. We calculated the kinetic parameters involved in the reaction network proposed and found evidence that the formation of octene proceeds mainly via the “cascade co-oligomerization” of re-adsorbed butene with ethylene.

A series of poly(lactic acid) (PLA), poly(butylene adipate-co-terephthalate) (PBAT) and glycidyl methacrylate-grafted poly(ethylene octene) (GPOE) blends and films with different GPOE content were prepared by melt blending and blowing film technique. The effect of GPOE on the rheological behavior, melt strength, crystallization behavior, crystallization morphology, miscibility, mechanical property, phase morphology, thermal stability and water vapor permeability were studied. The addition of GPOE improved melt rheological properties. Results of DSC showed that addition of GPOE encouraged the mobility of PLA molecular chains and enhanced crystalline ability. POM observations revealed that the addition of GPOE made the density of spherulite nucleation increase and the size of crystalline particles decrease. From DMA and SEM analysis, it was demonstrated that PLA/PBAT blend was an immiscible system and GPOE in the blend could improve compatibility between PLA and PBAT. Results of mechanical test showed that the PLA/PBAT/GPOE blends and films obtained had excellent mechanical properties. The elongation at break of 50/30/20 w/w/w PLA/PBAT/GPOE blend (477%) was higher by about 2.2 times than that of 70/30/0 w/w/w PLA/PBAT/GPOE blend (220%). The tensile strength of all the PLA/PBAT/GPOE blends exceeded 31 MPa. The tensile strength reached 32.9 MPa (MD) and 22.5 MPa (TD), the elongation at break exceeded 210% and tear strength exceeded 140 kN/m for 50/30/20 w/w/w PLA/PBAT/GPOE film. With increasing GPOE content, thermal stability and water vapor barrier property also improved.

The first enantioselective total synthesis of cerorubenic acid-III is described in detail. Different strategies and attempts, based on a type II [5+2] cycloaddition reaction, leading to the bicyclo[4.4.1] ring system with a strained bridgehead double bond, are depicted. Furthermore, sodium naphthalenide was found to be efficient in the chemoselective reduction of 8-oxabicyclo[3.2.1]octene, with three transformations completed in one operation. An unusual SN1 transannular cyclization reaction was applied to construct the synthetically challenging vinylcyclopropane moiety. This strategy enabled the total synthesis of cerorubenic acid-III in 19 steps.

Multiwalled carbon nanotubes obtained via the Catalytic Chemical Vapor Deposition method were covalently functionalised by maleic anhydride – α-octene copolymer via ‘grafting from’ approach using a...

Abstract A phosphine-containing porous polymer (TPDB), and a rhodium catalyst based on it, were synthesized. Proceeding from the relevant TEM, NMR, IR spectroscopy, and XPS data obtained, it was assumed that both the Rh(I) complexes and the Rh(0) nanoparticles that are stabilized in the polymer pores act as the catalyst’s active phase. The size of the nanoparticles (2–6 nm) is consistent with that of the polymer pores. The catalyst was tested in a model reaction of octene-1 hydroformylation at 2.0 MPa (CO : H2 = 1 : 1) in the temperature range of 60–120°C. It was demonstrated that the catalyst can be used repeatedly, and its activity remains constant from the third cycle of its use (aldehyde yield about 30% for 5 h, n/iso 2.5).

Oxidative cleavage of carbon–carbon double bonds (C═C) in alkenes and fatty acids produces aldehydes and acids valued as chemical intermediates. Solid tungsten oxide catalysts are low cost, nontoxi...

Kinetic modeling of ethylene oligomerization was performed; an Al-SBA-15-supported Ni catalyst and LiAlH4 co-catalyst were used to produce high-chain-length olefins in a one-pot reaction. A semi-batch slurry reactor produced kinetic data at different feed flow rates and temperatures. Grouping of the kinetic and mass transfer coefficients concerning the products was introduced to estimate undetermined parameters with limited experimental data. Among the four combinatorial cases, the estimation of individual kinetic parameters and grouped mass transfer coefficients showed the lowest errors and Akaike’s information criteria. The activation energies for the formation of hexene and octene were determined to be approximately 15 and 45 kJ/mol, respectively, confirming reported values of 23.1–64.1 kJ/mol. The model showed that the formation of short-chain-length olefins accounted for the rate-determining steps, and the evaluation for the effects of operating conditions guided optimal operation; high temperature and feed flow rate maximized heavy species production, and the flow rate should be optimized to maximize light olefin production.

The acidic properties of a selected SiO2–Al2O3 support material have been modified by steam-treating to study the influence on the formation of active nickel sites for butene oligomerization. For this purpose, the steam-treated supports were impregnated in situ with Ni (Cp)2. FTIR spectroscopy of pyridine adsorption revealed that the steaming procedure provokes changes of Bronsted as well as Lewis acid sites. In dependence on intensity of the steam-treatment, the amount of Bronsted acid sites decreases and weaker Al3+ Lewis acidic sites are created possibly in alumina-like agglomerates. Changes of the Al coordination sphere by steam-treatment was also confirmed by 27Al MAS NMR spectroscopy. The decrease of Bronsted acidity of the SiO2–Al2O3 support lowers its catalytic activity for the proton-catalyzed butene oligomerization, but the formation of active nickel sites on the differently treated supports under reaction conditions is not affected, as reflected by comparable activity of the respective Ni catalysts. As demonstrated by pyridine adsorption studies, mainly the weak Al3+ Lewis acidic sites (fivefold coordinated Al) created by steam-treatment were covered by Ni(Cp)2 impregnation, resulting in the formation of new, medium strong Ni2+ Lewis acidic sites which are active in coordinative catalysis. Although the Bronsted sites are only partly replaced by Ni, the remaining Bronsted sites have no influence on octene isomer distribution. It seems that the coordinative mechanism of oligomerization is generally preferred on Ni-impregnated samples.

UTKO1 is a synthetic analog of a natural tumor cell migration inhibitor, moverastin, isolated from microbial extracts of Aspergillus sp. 7720. UTKO1 was initially developed as a mixture of the stereoisomers. In this study, a concise and unified synthesis of the 4 optically active stereoisomers of UTKO1 was achieved from a known optically pure dihydro-α-ionone through a 5-step sequence. The key transformation in the synthesis was a Nozaki–Hiyama–Kishi (NHK) reaction between an optically active enoltriflate and a known aldehyde to install the chiral allylic hydroxy group at C2′. Simple chromatographic separation of the 2 diastereomers with regard to the allylic hydroxy group was possible by the derivatization into the corresponding acetals with Nemoto's optical resolution reagent, (S)- or (R)-5-allyl-2-oxabicyclo[3.3.0]octene (ALBO). All 4 synthetic stereoisomers of UTKO1 exhibited comparable tumor cell migration inhibitory activity.

The blends of ethylene-octene copolymers with octene content of 15 and 3 wt % and ethylene-vinyl acetate copolymer were studied by thermogravimetric analysis, differential scanning calorimetry, atomic force microscopy, and tensile experiments. Thermal behavior reveals that the addition of ethylene-octene copolymer improves the thermal stability of ethylene-vinyl acetate copolymer. Two single crystallization temperatures were detected. The surface morphology shows thin and elongated crystallites of neat ethylene-octene copolymer containing 3 wt % of octene and a bulky, random morphology for both the neat ethylene-octene copolymer containing 15 wt % of octane and ethylene-vinyl acetate copolymer, where a perfect mixture of aforementioned structures shows for 50/50 blend, with the immiscible domains of both ethylene-octene and ethylene-vinyl acetate copolymers. Additionally, the surface roughness of 50/50 blends is in between of the neat copolymers. All the experimental data confirms the immiscible nature of the blends. The mechanical properties of the binary blends were found to be between the values of the corresponding neat components.

Efficient and reliable synthesis of substituted hydrazinylpyridines in thick-wall ACE tubes via nucleophilic substitution of a chlorine substituent in different chloropyridines is presented. Hydrazine hydrate and alkylhydrazines were used as nucleophiles and simple alcohols and diethyl ether were the only organic solvents necessary, making the process environmentally and user friendly, potentially reaching 100% atomic efficiency. In the next step, transformations of succinic anhydride moieties fused to the bicyclo[2.2.2]octene framework into succinimide moieties via nucleophilic substitution of oxygens were conducted. As nucleophiles two of the synthesized hydrazinylpyridines (2-hydrazinyl-3-nitropyridine and 2-hydrazinyl-5-nitropyridine) and also hydrazine hydrate, phenylhydrazine, and 4-nitrophenylhydrazine were used. Reactions were again carried out in ACE tubes and only simple alcohols, diethyl ether, and acetone were needed as solvents. One of the prepared bicyclo[2.2.2]octene adducts displayed water solubility thus being a promising candidate for future studies as a novel bidentate ligand for various metal cations in aqueous solutions or acting as an unprecedented halogen bond acceptor.

We would like to acknowledge King Abdullah University of Science and Technology for funding. We also acknowledge the NMR core lab for their continuous help.

Maleic anhydride grafted ethylene octene copolymer toughened acrylonitrile butadiene styrene/polyamide 6 composites, strengthened with varying amounts of E-glass fibre (EG) were successfully develo...

The work studied the morphological, mechanical and thermal properties of poly(lactic acid) (PLA)/ethylene-octene copolymer (EOC) blends before and after adding the montmorillonite clay surface modified with 25-30% of octadecylamine (clay-ODA). The PLA/EOC blends and composites were prepared by melt mixing in an internal mixer. The EOC contents were 5, 10, 20, 30 wt% and clay-ODA contents were 1 and 3 phr. The morphology analysis showed that the addition of clay-ODA could improve the miscibility of PLA and EOC phases due to the domain size of dispersed EOC phase decreased with increasing clay-ODA content. X-ray diffraction revealed the formation of intercalated/exfoliated structure in PLA/clay-ODA and PLA blend composites. The mechanical properties showed that the impact strength of PLA/EOC blends dramatically increased with increasing EOC content up to 10 wt%. The strain at break of PLA blends increased with increasing EOC content. Moreover, the incorporation of clay-ODA increased significantly Young’s modulus of PLA and PLA/EOC blends with increasing clay-ODA content. The thermal stability of PLA/EOC blends improved with the addition of a small amount of clay-ODA.

The syntheses and crystal structures of the two title compounds, C11H10O3 (I) and C17H14BrNO2 (II), both containing the bicyclo[2.2.2]octene ring system, are reported here [the structure of I has been reported previously: White & Goh (2014). Private Communication (refcode HOKRIK). CCDC, Cambridge, England]. The bond lengths and angles of the bicyclo[2.2.2]octene ring system are similar for both structures. The imide functional group of II features carbonyl C=O bond lengths of 1.209 (2) and 1.210 (2) Å, with C—N bond lengths of 1.393 (2) and 1.397 (2) Å. The five-membered imide ring is nearly planar, and it is positioned exo relative to the alkene bridgehead carbon atoms of the bicyclo[2.2.2]octene ring system. Non-covalent interactions present in the crystal structure of II include a number of C—H...O interactions. The extended structure of II also features C—H...O hydrogen bonds as well as C—H...π and lone pair–π interactions, which combine together to create supramolecular sheets.

An efficient method for the synthesis of azabicyclo[5.1.0]octenes through cycloisomerization of nitrogen-tethered 1,7-enynes catalyzed by [IrCp*Cl2]2 was developed. With appropriately designed subs...

Comparative studies (gel permeation chromatography and evaluation of turbulent drag reduction effectiveness on a turbulence rheometer) of ultra-high molecular weight polymers from a series of higher alpha-olefins (hexene, octene, decene, dodecene) used as hydrodynamic drag agents have been carried out. It was found that the activity of hexene in the polymerization on a titanium magnesium catalyst, if all other relevant factors remain unaltered, significantly exceeds the activity of octene, decene, and dodecene (the conversion of hexene in 24 h is almost 1.5 times higher than the conversion of other monomers over the same time), and the rates of polymerization of the latter differ slightly. The average molecular weights of all polymers differ only slightly: ~6 millions Da for polyhexene and ~5 millions Da for all the others. At the same time, the drag reduction effectiveness of the polymers showed a significant dependence on the nature of the initial monomers: the drag reduction effectiveness rapidly diminishes with an increase in the molecular weight of the corresponding alpha-olefin (3–4 times upon transition from polyhexene to polydodecene).

This work studied the morphology, mechanical and thermal properties of poly (lactic acid) (PLA)/ethylene-octene copolymer (EOC) (80/20) blends with different organoclay types. Herein, EOC was introduced to toughening PLA by melt blending and organoclay was used to improve compatibility and tensile properties of the blends. The two organoclay types were nanoclay surface modified with aminopropyltriethoxysilane 0.5-5 wt% and octadecylamine 15-35% (Clay-ASO) and nanoclay surface modified with dimethyl dialkyl (C14-C18) amine 35-45 wt% (Clay-DDA). The organoclay contents were 3, 5 and 7 phr. Scanning electron microscope (SEM) observation results revealed PLA/EOC blends demonstrated a two-phase separation of dispersed EOC phase and PLA matrix phase. The addition of organoclay significantly improved the compatibility between PLA and EOC phases due to EOC droplet size decreased dominantly in PLA matrix, so organoclay could act as an effective compatibilizer. The incorporation of organoclay increased significantly tensile strength of PLA/EOC/organoclay composites while Young’s modulus increased with 5 phr of organoclay. The thermal stability of PLA/EOC blends did not change when compared with neat PLA, and when added Clay-ASO in the blends could improve the thermal stability of the PLA/EOC blends.

A novel multifunctional composite foam was fabricated by creating the tunable cellular structure in segregated poly(ethylene-co-octene) (POE)/carbon nanotube (CNT) composite through supercritical c...

β-Ketophosphonates, with the keto group linked to a bicyclo[3.3.0]oct(a)ene fragment, were synthesized starting from two diacids. These diacids were first transformed into internal anhydrides and one into a diester. The anhydrides and the diester were reacted with the lithium salt of dimethyl methanephosphonate to give two carboxy β-ketophosphonates, an ester β-ketophosphonate and a bis β-ketophosphonate in good yield. The ester β-ketophosphonate, obtained by two routes was used in the E-HEW selective olefination of a prostaglandin aldehyde with an α-side chain to give the 15-keto prostaglandin analogue in good yield. The compounds were characterized by elemental analysis, IR and high resolution 1H- and 13C-NMR spectroscopies.

The oxidation of octene-1 in aqueous organic solutions in the presence of bimetallic catalytic system (Pd (II)(PVP)-Cu(II)(PVP) (PVP - polyvinylpyrrolidone)) at 60–80 °C under mild conditions was studied. Kinetics, products and optimal reaction conditions were studied by the methods of kinetics, volumometry, gas chromatography and mass spectrometry. It have been found the optimal composition of the catalyst system [Pd(II)(PVP)]:[Cu(II)(PVP)]:[C8H16] = 1:(5–10):22. The maximum rate of oxygen absoprtion in most experiments was observed at 80 °C. Dimethylsulfoxide (DMSO) was used as solvent. The main reaction product was octanone-2 (34–70%). The maximum number of TONs was 236 mol of product/(mol Cat), and the maximum number of TOFs was 71 mol of product/ (mol of Cat⋅h).

The first (3 + 2)/(3 + 2) sequential annulation of γ-vinyl allenoates with alkylidenemalononitriles enabled by phosphine catalysis has been reported. A broad range of structurally dense tetra- and penta-substituted bicyclic[3,3,0]octene derivatives, containing a quaternary center and three sequential stereogenic center, were synthesized in good to excellent yields. In this approach, three new C-C bonds are formed in one pot, and εC and αC of γ-vinyl allenoate are two electrophilic centers, whereas its γC exhibits nucleophilic reactivity.

Laboratory studies have been conducted to explore the possibility of obtaining poly-α-olefin oil PAO-20 under flow conditions on the basis of the domestic industrial octene fraction of α-olefins. The features of cationic oligomerization have been revealed by varying the catalyst concentration and the reaction temperature; process parameters to ensure the maximum yield of desired target product have been determined.

We report on electrical insulating materials that not only have sufficient mechanical toughness to survive use conditions but also possess the ability to undergo thermally induced self-repair when damaged. By controlling the cross-link density, a modified ethylene–octene copolymer (EOC) is able to retain its self-healing abilities while also being used at temperatures greater than the original, unmodified polymer. Specifically, an EOC cross-linked with 0.25 wt % dicumyl peroxide affords a material ability to recover 61% of its critical fracture energy—a value similar to thermoplastic EOC. Furthermore, as shown by dielectric spectroscopy, the cross-linked EOC retains good electrically insulating properties.

In this study, the authors synthesized myristyl methacrylate monomers by esterification reaction of methacrylic acid and myristyl alcohol using conc. H2SO4 as catalyst. Homopolymer of the prepared ...

A concise and enantioselective total synthesis of (+)-jungermatrobrunin A (1), which features a unique bicyclo[3.2.1]octene ring skeleton with an unprecedented peroxide bridge, was accomplished in 13 steps by making use of a late-stage visible-light-mediated Schenck ene reaction of (-)-1α,6α-diacetoxyjungermannenone C (2). Along the way, a UV-light-induced bicyclo[3.2.1]octene ring rearrangement afforded (+)-12-hydroxy-1α,6α-diacetoxy-ent-kaura-9(11),16-dien-15-one (4). These divergent photo-induced skeletal rearrangements support a possible biogenetic relationship between (+)-1, (-)-2, and (+)-4.

Using the method of deformation calorimetry based on the simultaneous precision registration of mechanical and thermal effects, the mechanism of uniaxial deformation of low-crystallinity ethylene-octene copolymers (α = 4–18%) characterized by unique stress–strain properties is studied. It is shown that changes in the internal energy play a considerable role in the deformation of the studied copolymers. Changes in the entropy and internal energy during deformation are determined. Intra- and intermolecular energy contributions are estimated, and their ratio is shown to be controlled by both the level of crystallinity and the value of strain. It is found that intermolecular changes, which are associated with destruction of the initial structure and which grow with an increase in the degree of crystallinity, prevail at the initial step of deformation, while the region of large deformations is controlled by intrachain conformational transitions occurring in amorphous regions. An analysis of intermolecular energy changes, including cyclic ones, demonstrates the absence of intense effects that are generally caused by stress-induced crystallization; however, the possibility of low-order ordering should not be excluded.

Summary Herein, we describe the protecting-group-free total synthesis of two structurally diverse Isodon diterpenoids, (+)-ent-kauradienone (3) and (−)-jungermannenone C (4), in 12 and 14 steps respectively, through sequential applications of three radical-based reactions, including the photoinduced skeletal rearrangements of bicyclo[3.2.1]octene ring systems. Further investigations of this photochemical radical rearrangement on a series of diverse terpenoids demonstrated both the unparalleled functional-group tolerance and the broad applicability of such late-stage photochemical rearrangements for the synthesis of structurally diverse and complex small molecules. Overall, the mild nature of late-stage photoinduced skeletal rearrangements might suggest that they are possible in a biological setting in unappreciated complimentary biosynthetic pathways.

Ag/γ-Al2O3 catalysts, containing 5 and 25 wt% Ag, were synthesized by the slurry phase impregnation method. They were tested for the liquid phase continuous flow preferential hydrogenation of octanal in a mixture with octene. The catalysts were characterised by XRD, IR, BET, SEM, TEM and NH3-TPD. These catalysts showed strong preference for octanal hydrogenation, irrespective of reaction temperature or silver loading. A maximum octanal conversion of 90% with selectivity towards octanol of 94% was achieved over 25 wt% Ag/γ-Al2O3 at 180 °C with minimal octene conversion (

A facile methodology for improving the crystallization ability, rheological properties and microcellular foaming behaviors of poly (lactic acid)/low-density polyethylene (PLA/LDPE) blends through compatibilization was proposed. Poly (ethylene octene) grafted with glycidyl methacrylate (GPOE) as reactive compatibilizer was introduced into PLA/LDPE blends and the resultant PLA/LDPE/GPOE blends were foamed by supercritical CO2. Torque curves and Fourier transformation infrared spectroscopy results confirmed that GPOE reacted with PLA successfully. The crystallization ability and rheological properties of PLA was promoted obviously by the addition of LDPE and GPOE. The size of LDPE dispersion phase in PLA/LDPE blends decreased from 4.4 ± 0.1 to 1.2 ± 0.1 µm, owing to the compatibility effect. When the content of GPOE reach 8 phr, microcellular structure appeared in the PLA/LDPE/GPOE blending foam. An interesting flower-like cellular structure was observed in PLA/LDPE/GPOE blending foams, with the foaming temperature at 85 and 90 °C. Finally, the microcellular foaming mechanism for various PLA foams was proposed and clarified using schematic diagram.

The effects of the montmorillonite clay surface modified with 0.5-5 wt% aminopropyltriethoxysilane and 15-35% octadecylamine (Clay-APTSO) on morphology, mechanical and thermal properties of poly(lactic acid) (PLA)/ethylene-octene copolymer (EOC)/Clay-APTSO composites were investigated. The blends of PLA/EOC with and without Clay-APTSO were prepared by melt mixing in an internal mixer. Scanning electron microscopy analysis observed the morphology of PLA/EOC blends demonstrated a phase separation of minor phase and matrix phase. The addition of Clay-APTSO in PLA/EOC blends showed significant decreased in droplet size of dispersed EOC phase, thus, Clay-APTSO acted as an effective compatibilizer in the PLA/EOC blends. The results of tensile properties found the decrease of Young’s modulus of PLA when added EOC due to the low modulus and flexibility of EOC. While the incorporation of Clay-APTSO increased significantly Young’s modulus of PLA/EOC blends at low EOC and Clay-APTSO content. The strain at break of the blends increased with the increase of EOC loading, this indicated the presence of EOC enhanced the elongation at break of PLA, while the addition Clay-APTSO reduced the strain at break of PLA/EOC blends. The tensile strength of all blend compositions improved when added Clay-APTSO and the tensile strength showed the highest value at 3 phr of Clay-APTSO. The thermal stability of PLA/EOC blends did not change when compared with neat PLA, and when added Clay-APTSO in the blends could improve the thermal stability of the PLA/EOC blends.

Recycled poly(ethylene terephthalate) (R-PET)/high-density polyethylene (HDPE)/glycidyl methacrylate grafted poly(ethylene-octene) (mPOE) blends, in which the binary (HDPE/mPOE) dispersed phase was of a HDPE core-mPOE shell structure, were prepared. For this purpose, HDPE-g-mPOE graft copolymers were prepared in HDPE/mPOE blends via reactive extrusion with the presence of the free radical initiator dicumyl peroxide (DCP). Then, R-PET was blended with the HDPE/mPOE blends by melt extrusion. The effect of the DCP and mPOE content in the HDPE/mPOE blends on the phase morphology and mechanical properties of the R-PET/HDPE/mPOE blends were studied systematically. It was found that the blends containing reactive compatibilizer exhibited the encapsulation of the HDPE by the mPOE, forming core–shell particles dispersed phase morphology. The graft chains of HDPE-g-mPOE-g-PET formed by the in situ reaction between R-PET and mPOE phases reduced the interfacial tension. Consequently, the dispersed phase morphology was observed to form smaller diameter core–shell particles. The resultant blends exhibited an effect on both the thermal and mechanical properties. Differential scanning calorimetric analysis showed the dispersed phase particles could act as a nucleating agent in the R-PET matrix to improve the crystallization temperature, while the graft copolymers formed in the compatibilized R-PET/HDPE/mPOE blend decreased the nucleation activity. Notched Charpy impact strength and elongation at break of the R-PET were improved by forming the core–shell particles dispersed phase morphology.

The mechanical properties and the structural transformations occurring during deformation of some commercial grades of ethylene/1-octene multiblock copolymers (OBCs) obtained from chain shuttling technology are analyzed. The samples are characterized by a statistical multiblock architecture, where soft and amorphous blocks with high octene concentration (approximate to 18.9 mol %) alternate with hard and crystalline blocks with low octene concentration (approximate to 0.5 mol %). The length of blocks (BL) and the number of blocks/chain (NB) change from chain to chain according to a statistical distribution. The selected samples have molecular mass in the range 85-130 kg/mol, percentage of hard segments in the range 15-27%, and a melting temperature of approximate to 120 degrees C. The average molecular masses of the hard blocks M-H and soft blocks M-S are in the ranges 2-3 kg/mol and 6-15 kg/mol, respectively, whereas the number of blocks/chain is in between 2 and 17. Even though the samples are characterized by similar octene concentration, small difference in molecular mass, and fractional content of hard blocks, they show remarkable differences of mechanical properties, depending on the average BL and NB values, encompassing from those of strong elastomers, in the case of samples with low block length and high number of blocks/chain, to those of soft elastomers, in the case of samples with high block length and low number of blocks/chain. The differences in the mechanical properties of OBC samples are amplified by stretching at high temperatures. Not previously stretched films obtained by compression molding show only partial recovery of the initial dimensions in mechanical cycles of stretching and releasing the tension, with values of recovered strain higher than 50% at 25 degrees C. However, the resultant specimens obtained by release of the tension show good elastomeric properties in a wide deformation range at 25 degrees C and, in the case of the samples with high strength, also at 60 degrees C. Fiber diffraction analysis reveals that by stretching at high deformation the orientation of the crystals is accomplished by mechanical melting and formation of an oriented amorphous phase, namely, involving the hard segments extracted from the crystals. Upon releasing the tension recrystallization occurs, and the high degree of orientation achieved by the crystals and amorphous phase is lost.

Novel extended BODIPYs fused with bicyclo rings were synthesized from bicyclopyrroles by combining Knoevenagel condensation, Suzuki coupling, and O-chelation. The absorption maxima of the BODIPYs ranged from the visible to near-infrared region and the compounds showed good solubility in organic solvents. The solubility of the bicycloBODIPY with 2-naphthyl groups at the α-position of the pyrrole units was particularly high. Heating converted distyrylBODIPY with bicyclo[2.2.2]octene to benzoBODIPY with absorption (748.5 nm) and fluorescence (775.0 nm) in the near-infrared region.

We studied the microstructure–rheology relationship of polypropylene (PP)/ethylene octene copolymer (EOC) blends by means of rheology in combination with scanning electron microscopy. The blends varying in blend ratio all prepared by melt mixing were considered. The results of the frequency sweep experiment performed on the blend sample with matrix-dispersed morphology showed a pronounced positive deviation of storage modulus values at a low frequency range from those predicted by Palierne’s viscoelastic model. This could be explained in terms of EOC droplets interconnectivity which was generated by in situ increased chain-branched entanglements. That is, the thermo-mechanically induced PP macro-radicals produced during the melt mixing could graft onto the more stable EOC macro-radicals in the interface leading to much longer-chain-branched EOC molecules, which had the capability of creating favorable entanglements for the EOC droplets conductivity.

Blends of two biobased polymers, poly(lactic acid) and poly(trimethylene terephthalate) (PTT), were compatibilized with either maleic anhydride-grafted poly(ethylene-octene) (mPOE) or organically modified clay (Cloisite 30B). Dynamic rheological measurements revealed that the mPOE inclusion resulted in a four-fold increase in viscosity relative to the noncompatibilized blends. By loading 3 wt% Cloisite 30B, the storage moduli of the blends showed a distinct solid-like behavior and high complex viscosity in the low-frequency region, which can be interpreted by the reduced sizes of the PTT phase evidenced from the scanning electron microscopy (SEM) micrography. A temperature sweep of the viscosity of the blends starting from 180°C revealed that the existence of an unmelted PTT dispersed phase might impede the decline in viscosity with increasing temperature near the melting point of PTT. The introduced compatibilizers can restrict the temperature-dependent morphology evolution, and the use of the 3 wt% 30B clay can prohibit the morphology evolution during the temperature sweep.

The Diels–Alder cycloaddition between bisdienes and bisdienophile incorporating the 7-oxa-bicyclo[2.2.1]heptane unit are well known to show high diastereoselectivity that can be exploited for the synthesis of molecular belts. The related bisdiene 5,6,7,8-tetramethylidene-2-bicyclo[2.2.2]octene is a valuable building block for the synthesis of photoprecursors for acenes, but it has not been employed for the synthesis of molecular belts. The present work investigates by computational means the Diels–Alder reaction between these bisdiene building blocks with syn-1,4,5,8-tetrahydro-1,4:5,8-diepoxyanthracene, which shows that the diastereoselectivity of the Diels–Alder reaction of the etheno-bridged bisdiene is lower than that of the epoxy-bridged bisdiene. The reaction of the etheno-bridged bisdiene and syn-1,4,5,8-tetrahydro-1,4:5,8-diepoxyanthracene in 2:1 ratio yields two diastereomers that differ in the orientation of the oxa and etheno bridges based on NMR and X-ray crystallography. The all-syn diastereomer can be transformed into a molecular belt by inter- and intramolecular Diels–Alder reactions with a bifunctional building block. The molecular belt could function as a synthetic intermediate en route to a [11]cyclacene photoprecursor.

Poly(ethylene-co-octene) (POE) elastomers with different copolymer compositions and molecular weight exhibit quite distinctive foaming behaviors and dimensional stability using supercritical carbon dioxide (CO2) as a blowing agent. As the octene content decreases from 16.54% to 4.48% with constant melting index of 1, both the melting point and crystallinity of POE increase, due to the increase in fraction of ethylene homo-polymerization segment. the foaming window of POE moves to a narrow higher temperature zone from 20–50 °C to 90–110 °C under 11 Mpa CO2 pressure, and CO2 solubility as well as CO2 desorption rate decrease, so that the average cell diameter becomes larger. POE foams with higher octene content have more serious shrinkage problem due to lower compression modulus, weaker crystal structure and higher CO2 permeability. As POE molecular weight increases at similar octene content, there is little effect on crystallization and CO2 diffusion behavior, the foaming window becomes wider and cell density increases, mainly owing to higher polymer melt strength, the volume shrinkage ratio of their foams is less than 20% because of similar higher polymer modulus. In addition, when the initiate expansion ratio is over 17 times, POE foams with longer and thinner cell wall structures are more prone to shrinkage and recovery during aging process, due to more bending deformation and less compression deformation.

In recent decades, bicyclic nitroxyl radicals have caught chemists’ attention as selective catalysts for the oxidation of alcohols and amines and as additives and mediators in directed C-H oxidative transformations. In this regard, the design and development of synthetic approaches to new functional bicyclic nitroxides is a relevant and important issue. It has been reported that imidazo[1,2-b]isoxazoles formed during the condensation of acetylacetone with 2-hydroxyaminooximes having a secondary hydroxyamino group are recyclized under mild basic catalyzed conditions to 8-hydroxy-5-methyl-3-oxo-6,8-diazabicyclo[3.2.1]-6-octenes. The latter, containing a sterically hindered cyclic N-hydroxy group, upon oxidation with lead dioxide in acetone, virtually quantitatively form stable nitroxyl bicyclic radicals of a new class, which are derivatives of both 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (TEMPON) and 3-imidazolines.

A photoinduced pericyclic cascade reaction has been developed to afford oxabicyclo[4.2.0]octenes. Mechanistic studies show that this reaction undergoes [2 + 2]-photocycloaddition, base-promoted elimination, retro-4π-electrocyclization, [1,5]-H shift, and 4π-electrocyclization procedures. This reaction features wide substrate scope, good functional group tolerance, and excellent diastereoselectivity.

The synthesis of β-ketophosphonates, linked by a methylene group to a bicyclo[3.3.0]octene fragment, was performed by the reaction of dimethyl methanephosphonate with the ester group of two intermediates with this scaffold. Starting from a diol, protected with good leaving groups (mesyl and tosyl), we performed a sequence of reactions with good yields: the carbon chain lengthening by reaction with KCN, the hydrolysis of the nitrile groups to carboxyl, the esterification of carboxyl to ester and finally the phosphonate synthesis, which gave one bis-β-ketophosphonate and two mono β-ketophosphonates. The new β-ketophosphonates are key intermediates for obtaining new prostaglandin analogues with a bicyclo[3.3.0]octene fragment in the ω-side chain. The bicyclo[3.3.0]octane scaffold, found in natural products and in anticancer compounds, are expected to keep their activity in PG analogs; the bulky scaffold, separated by a methylene group from the C-15 carbon atom, is expected to diminish the inactivation of the PG analog by enzyme oxidation of 15α-OH oxidation to 15-Keto via PGDH pathway.

Thermoplastic polymers like ethylene-octene copolymer (EOC) may be grafted with silanes via reactive extrusion to enable subsequent crosslinking for advanced biomaterials manufacture. However, this reactive extrusion process is difficult to control and it is still challenging to reproducibly arrive at well-defined products. Moreover, high grafting degrees require a considerable excess of grafting reagent. A large proportion of the silane passes through the process without reacting and needs to be removed at great expense by subsequent purification. This results in unnecessarily high consumption of chemicals and a rather resource-inefficient process. It is thus desired to be able to define desired grafting degrees with optimum grafting efficiency by means of suitable process control. In this study, the continuous grafting of vinyltrimethoxysilane (VTMS) on ethylene-octene copolymer (EOC) via reactive extrusion was investigated. Successful grafting was verified and quantified by 1H-NMR spectroscopy. The effects of five process parameters and their synergistic interactions on grafting degree and grafting efficiency were determined using a face-centered experimental design (FCD). Response surface methodology (RSM) was applied to derive a causal process model and define process windows yielding arbitrary grafting degrees between &lt, 2 and &gt, 5% at a minimum waste of grafting agent. It was found that the reactive extrusion process was strongly influenced by several second-order interaction effects making this process difficult to control. Grafting efficiencies between 75 and 80% can be realized as long as grafting degrees &lt, 2% are admitted.

In Diels&ndash, Alder reactions, 2H-pyran-2-ones as dienes can yield a large variety of cycloadducts with up to four contiguous carbon stereogenic centers. Some of the potentially most useful, however difficult to prepare due to their low thermal stability, are the primary CO2-containing oxabicyclo[2.2.2]octenes, which could be formed as eight distinctive isomers (two sets of regioisomers, each of these composed of four different stereoisomers). A high-pressure synthesis of such products was recently described in a few cases where vinyl-moiety-containing dienophiles were used as synthetic equivalents of acetylene. However, structures of the primary products have been so far only rarely investigated in detail. Herein, we present seven novel single-crystal X-ray diffraction structures of such cycloadducts of both stereoisomeric forms, i.e., endo and exo. Additionally, we present a single-crystal structure of a rare case of a cyclohexadiene system stable at room temperature, obtained as a secondary product upon the retro-hetero-Diels&ndash, Alder elimination of CO2 under thermal conditions (microwave irradiation), during this elimination the symmetry is increased and out of eight initially possible isomers of the reactant, this number in the product is decreased to four. In oxabicyclo[2.2.2]octene compounds, centrosymmetric hydrogen bonding was found to be the predominant motif and diverse supramolecular patterns were observed due to rich variety of C&ndash, H⋯O and C&ndash, H⋯&pi, interactions.