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• PISBFs were prepared from 2,5-dimethylfuran dicarboxylate, isosorbide and butanediol. • PISBFs had T D,5% values higher than 370 °C and T DM higher than 405 °C. • PIS 40 B 60 F had a Tg 87 °C, a Young's modulus 1400 MPa and an elongation at break 173%. Fully biobased copolyesters poly(isosorbide- co -butylene 2,5-furandicarboxylate) (PISBF) were synthesized from 2,5-dimethylfuran dicarboxylate (DMFD), isosorbide (IS) and 1,4-butanediol (BDO) via transesterification and polycondensation reactions. The resulting copolymers were characterized by 1H NMR, 13C NMR, GPC, intrinsic viscosity, DSC, TGA and tensile testing, respectively. The NMR characterizations had confirmed that BDO was successfully introduced into the poly(isosorbide 2,5-furandicarboxylate) (PIF) polyester chains. Over the IS experimental composition range 20–80 % in copolymer chains, PISBF copolymers had T D, 5% values higher than 370 °C and T DM higher than 405 ° C, and Tg values within the range of 55 °C and 150 °C. Introduction of BDO units into PIF chains imparted the PISBF copolyester with better mechanical performance than PIF, thus PISBF copolyesters with IS content of 20–50% were strong and toughened copolymers with Young's modulus about 1400 MPa, tensile strength at break higher than 53 MPa, and elongation at break higher than 46%. [ABSTRACT FROM AUTHOR]

• Based on the processing temperature of PEN, a highly efficient nucleating agent was screened. • Intrinsic viscosity provides evidence of chemical nucleation of carboxylates in PEN. • Under the verification of WAXD, the HPN-68L did not change the PEN crystal type. • The nucleating agent dosage is only 0.2 wt% to achieve the best effect. Bicyclic [2.2.1] heptane-2,3-dicarboxylic acid disodium salt (HPN-68L) and poly(ethylene 2,6-naphthalate) (PEN) blends were prepared by using a twin-screw extruder. The effects of HPN-68L on the crystallization behavior, intrinsic viscosity and mechanical properties of PEN were systematically investigated. The results showed that HPN-68L shows a significant nucleation effect on PEN. The nucleation efficiency basically increased with the increase of HPN-68L content and reached up the maximum value of 53.27% when the HPN-68L was 0.4%. However, the degree of crystallinity of PEN raised up firstly and then decreased with the increasing of HPN-68 content. So the optimized content of HPN-68L is 0.2 wt% and the crystallization peak temperature of PEN apparently increased by 8.74 °C with the addition of 0.2 wt% HPN-68L during the cooling process. But the corresponding mechanical properties including toughness and elongation-at-break(%) were the worst. The reason were discussed. Additionally, the nucleation mechanism were also proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • PEThF copolyesters were synthesized in the presence of 10–40 mol% TDCA. • PEThFs are amorphous copolymers, with T g slightly decreasing with ETh unit content. • Brittle-ductile transition occurred for PEThF with ETh unit content as low as 10 mol%. • PETh 20 F manifested ductile fracture and maintained performance advantages of PEF. • PETh 20 F showed elongation 21%, T g 84 °C, modulus 3.2 GPa, strength 62 MPa and oxygen barrier 5.4 times to PET. Poly(ethylene 2,5-furandicarboxylate) (PEF) is an important biobased polyester with not only high glass transition temperature (T g), excellent strength and rigidity but also superior gas barrier properties. However, its poor ductility could limit its applications. In this study, 2,5-thiophenedicarboylic acid (TDCA) was used to modify PEF by copolycondensation. By introducing 10–40 mol% TDCA, poly(ethylene 2,5-thiophenedicarboxylate-co-2,5-furandicarboxylate) (PEThF) copolyesters with intrinsic viscosity of 0.63–0.77 dL/g were synthesized and characterized with 1H NMR, DSC, TGA, etc. The copolyesters are all amorphous polymers. Brittle-ductile transition was observed during tensile testing of PETh 10 F (PEThF containing 10 mol% 2,5-thiophenedicarboxylate unit). PEThFs containing 20–30% 2,5-thiophenedicarboxylate unit showed not only clearly improved ductility but also well-maintained performance advantages of PEF including high T g (84–81 °C), modulus (∼3.2 GPa), strength (yielding 95 MPa, breaking 60 MPa) and oxygen barrier (5.4–5.0 times PET). [ABSTRACT FROM AUTHOR]

The intrinsic viscosities, [ η ], of the 3-arm star polyelectrolyte in pure water are for a given molar mass considerably lower than for the linear product because of the higher monomer concentration and charge density in isolated coils. These effects are much more pronounced than in the case of uncharged macromolecules. Extra salt (NaCl, NaI, CaCl 2 ) reduces the solution viscosities of the 3-arm star polymer less than of the linear product. The transition of [ η ] from the value in pure water to the minimum saturation value at high salt concentrations follows a Boltzmann sigmoid. In saline solvents the changes of the viscosities with rising polymer concentration depend strongly on the chemical nature of the salt and on the molecular architecture of the solute. The present findings demonstrate the necessity to account for thermodynamic interactions between all components of the mixture, in addition to the usual electrostatic considerations. These considerations should turn out helpful for a better understanding of salt induced topological transitions of charged biopolymers. [ABSTRACT FROM AUTHOR]

Facile and quantitative method to introduce primary-amino group into the distal chain end of poly(2-substituted 2-oxazoline)s (POx)s, which have attracted progressive interest as platform polymers for various bio-functionality materials, was established here via two-step reactions; First, termination of cationic polymerization of 2-oxazoline using sodium azide as the end-capping reagent, followed by the conversion of the azido group to an amino group using triphenylphosphine (TPP) by the Staudinger reaction. The azido introduction step and the subsequent amino conversion step was accomplished within 1 h and 3 h, respectively, to ultimately obtain ω-amino-poly(2-ethyl-2-oxazoline) (PEtOx-NH 2 ) with 96% functionality. The synthesized PEtOx-NH 2 was subjected to ring-opening polymerization of N ε -trifluoroacetyl- l -lysine N -carboxy anhydride (Lys(TFA)-NCA) to successfully obtain the block copolymer PEtOx- b -PLys(TFA), which can be utilized as a platform polymer to develop polymer therapeutics, thus, demonstrating the versatility of the presently reported procedure for further functionalization of POx derivatives. [ABSTRACT FROM AUTHOR]

Intrinsic viscosities, generalized intrinsic viscosities and viscometric interaction parameters were measured for aqueous solutions of poly(ethylene oxide) [ PEO ], poly( N,N -dimethyl aminoethyl methacrylate) [ PR ] (uncharged) and for poly{[2-(methacryloyloxy)ethyl] trimethylammonium iodide} [ PR + ] (charged) within a wide range of molar masses. In this manner it was possible to establish the information required for the study of non-additivity effects upon the formation of binary copolymers from the monomers specified above. The following additional items were of particular interest: The effects of charging PR to PR + and the composition dependence of the coil overlap in the case of saline (NaCl, CaCl 2 and NaI) solvents. NaCl turned out to be much less efficient in shielding the electrostatic interactions than the other salts due to its large tendency to form ion pairs in solution. [ABSTRACT FROM AUTHOR]

Copolymers of ethylene oxide (EO) and N,N -dimethyl aminoethyl methacrylate (R) or [2-(methacryloyloxy)ethyl] trimethylammonium iodide (R + ) were studied in dilute solution: P ( EO p – b – R n ) ( I ) , P(R n (1− f ) – ran – R + n f ) ( II ) , and P ( EO p – b – R n + ) ( III ) ; n and p give the numbers of monomers and f is the degree of charging. For II (variable f ) and III (variable n ) the effects of charging on the intrinsic viscosities [ η ] are well described by Boltzmann sigmoids. The deviation of [ η ] from [ η ] add (calculated from the corresponding homopolymer data, assuming additivity of the individual contributions) are quantified by σ = [ η ] / [ η ] add - 1 measuring the segregation ( σ > 0 ) or clustering ( σ < 0 ) of dissimilar monomers in isolated coils. For II , σ changes from negative at low f to positive at high f . I and III pass maxima as n becomes larger, where σ is positive at low and negative at high n for I , but always larger than zero for III . The investigation of salt effects using NaCl, CaCl 2 and NaI corroborates the observations for the homopolymers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hofmeister anions interact reversely for high viscosity negatively charged polymers. • Anions interact based on the sequence for polyelectrolyte/polyampholyte complex. • Anions can be used to tune the properties and drug release profiles. Alginate and gelatin are bio-polymers widely used in drug delivery. A range of salts can be used to achieve the required flexibility in biomaterial design. Hofmeister series gives an idea about the behaviour of salts with proteins. However, its application for the design of biomaterials and their specific effect on high-viscosity polymers and polymer mixtures has not quite been explored. Firstly, this work proposes a strategic interaction-based approach for designing a dual-drug ocular biomaterial. Secondly, the impact of different salt anions on gelatin and alginate mixture for the developed protocols is studied by a proposed method of determining shear-dependent general intrinsic viscosity. Thirdly, shear-dependent intrinsic viscosity is used to determine the interaction amongst the polymers in their mixture, which is then correlated to the release profiles and hydrodynamic radii of polymer mixtures. It is observed that Hofmeister anions behave reversely for high-viscosity negatively charged polymers and depends on the charge densities of the anions. For the polyelectrolyte/polyampholyte complex/mixture, the interactions depend on the addition sequence. It is inferred that the kosmotropes are preferred for protocols where salt is added between gelatin and alginate and chaotropes for protocols where salt is added to the gelatin and alginate complex/mixture in terms of release profiles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electron-beam irradiation up to 100 kGy has an insignificant on chemical structure of poly(HEMA). • Intrinsic viscosity measurements and size exclusion chromatography confirmed the propensity to undergo chain scission. • The radiation sensitivity of poly(HEMA) is thought to be due to the limited ester side chain mobility hindering radical recombination as well as hydrogen bonding. • Acetaldehyde and carboxyl compounds were identified as the main products of polymer radiolysis. The understanding of the radiation-induced degradation mechanisms of polymers is essential towards developing new application implying radiation technology. This study reports on the effect of electron-beam (EB) radiation on linear poly(2-hydroxyethyl methacrylate) upon exposure to 5–100 kGy doses. Various spectroscopic and analytic methods were used to monitor the effects of EB radiation to assess poly(HEMA) reactivity during irradiation in the solid amorphous state. Intrinsic viscosity measurements and molecular weight (MW) determination using size exclusion chromatography (SEC) confirmed the propensity to undergo chain scission. The radiolytic yields for cross-linking and scission were assessed. Spectroscopic data allow to propose a reasonable mechanism accounting for these observations. [ABSTRACT FROM AUTHOR]

The resultant polydiene-based polymer brushes can act as the template to prepare superhydrophobic polymer brush-nanoparticle hybrid coatings which possessing superhydrophobic and antifouling characteristics. [Display omitted] • Macroinitiators with multi-site and high-fidelity terminal chlorine groups. • Structurally controllable anisotropic polymer brushes. • Low intrinsic viscosity and high terminal group functionality. • Superhydrophobic and antifouling polymer brush-nanoparticle hybrid coatings. Polymer brushes have garnered widespread attention for their potential applications in some emerging fields such as antifouling coating, drug delivery and high-efficiency catalyst. However, the difficulties in precisely controlling the structure and composition of polymer brushes severely degraded their physicochemical properties and chemical conformation. Herein, we developed an effective strategy to prepare structurally controllable atom transfer radical polymerization (ATRP) macroinitiator using multi-site polydienes as the polymer backbone and chlorine as the modifier. The amount of grafting allyl chloride groups could be effectively adjusted by regulating the reaction time, thereby achieving the programming ATRP macromolecular initiator with high-fidelity terminal chlorine groups. Thereinto, with chlorinated polydienes as the ATRP macroinitiator and polymer backbone, and resultant polystyrene as the side chains, the well-defined polystyrene brushes bearing controlled worm-like and rod-like structures were obtained. Benefiting from the branched structure, polystyrene brushes exhibited low intrinsic viscosity, compact molecular dimensions, and high terminal group functionality. Further, we prepared novel a superhydrophobic nanomaterial, namely, SiO 2 nanoparticles (NPs)-polymer brushes, which demonstrated high non-wetting and excellent antifouling performance. Consequently, the approach and results collectively provide a promising avenue and perspective for preparing brush-like polymers with precisely designed structures and functionality. [ABSTRACT FROM AUTHOR]

In the current study the effect of different mesoporous silica particles like MCF and SBA-15 on the solid state polymerization (SSP) of poly(ethylene terephthalate) (PET) was investigated. PET nanocomposites containing 1 and 2.5 wt% SBA-15 silica (average pore diameter 4.7 nm) and MCF silica (average pore diameter 14.2 nm) have been prepared by in-situ polymerization. All nanocomposites have been characterized using FTIR spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). SSP was conducted at 220, 230 and 240 °C for 1, 2, 3 and 4 h under vacuum. Intrinsic viscosity (IV) measurements after solid-state polymerization of nanocomposites revealed that PET/SBA-15 nanocomposites exhibited lower IV increase compared to neat PET, while the opposite was observed for PET/MCF nanocomposites, especially for 1 wt% MCF content. A simple kinetic model was employed to predict the time evolution of IV, as well as the carboxyl and hydroxyl content during SSP at different temperatures and reaction times. [ABSTRACT FROM AUTHOR]

Different polymorphs are developed in isotactic poly(propylene- co -1-heptene) copolymers depending on 1-heptene molar content and thermal history: monoclinic and orthorhombic crystallites as well as mesomorphic entities. Indentation hardness values and deformability are found to be related to those variables as well as to crystallinity degree. Consequently, mechanical behavior can be tailored mainly by varying all of these parameters and a range from rigid to soft and more easily deformable materials is attained by synthesis of copolymers based on isotactic propylene with 1-heptene as comonomeric unit. Evaluation of the influence of molecular weight, intrinsic viscosity and microstructural details is also performed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Relation between contraction factors of long-chain branched macromolecules is defined. [•] The exponent is MW-independent only for molecules with identical architecture. [•] The volume fraction of polymer segments within the domain of a molecule is estimated. [Copyright &y& Elsevier]

Abstract: Long-chain branching (LCB) is a well-known structural phenomenon in polyethylene whose characterization is of main interest because it affects a lot of properties of these polymers. Quantification of LCB can be carried out by GPC-VIS (gel permeation chromatography with a viscometer detector to determine the intrinsic viscosity) and by GPC-MALS (GPC with multi-angle light scattering detector to determine the radius of gyration) by calculating branching indexes with a linear reference sample and finally the LCB (λ) distribution. Usually, both techniques are used to determine the value of λ and its distribution, but taking into account that its value can be low there is fundamental establish the range of application in function of the uncertainties on the results. In this work, a numerical method, previously developed for the reduction of GPC-MALS data, has been used with GPC-VIS data and extended to determine branching indexes and LCB. Final results obtained by GPC-MALS and GPC-VIS were compared with special focus to ranges of application and reproducibility of the results. Branching indexes allowed evaluating the structure factor in function of molecular weight and a qualitative dependence with polydispersity index was found. Distribution of LCB with molecular weight has been determined and reproducibility checked in order to establish the limitations of each technique and the corresponding range of application. [Copyright &y& Elsevier]

Abstract: This paper reports the synthesis of 4-arm poly(tert-butyl acrylate) stars of different molar masses up to 106 g/mol by the “core-first” method using ATRP. All obtained stars have a monomodal and narrow molar-mass distribution (<1.2). The dilute-solution properties of these star polymers were investigated in good solvents (tetrahydrofuran and acetone). Gel permeation chromatography and dynamic and static light scattering were used to measure the hydrodynamic properties including intrinsic viscosity [η], radius of gyration Rg , hydrodynamic radius Rh , second virial coefficient A2 and diffusion coefficient D0 . These data were used to establish relationships between these parameters and the molar mass of 4-arm poly(tert-butyl acrylate) stars. The branching parameters g and g ′ and the shape factor ρ were calculated for all obtained star polymers. [ABSTRACT FROM AUTHOR]

Abstract: The Hansen Solubility Parameter (HSP) and the Flory Huggins polymer–solvent interaction parameter of three SBS (styrene–butadiene–styrene triblock copolymer) rubbers have been determined by using intrinsic viscosity (IV) measurements. The obtained values indicated that, although all the tested compounds could be adequate as solvents, the aromatic ones are the most compatible for this kind of polymers. From these previous data, the activity coefficients of the solvent were also obtained and fitted to NRTL model. The calculated interaction parameters have a great importance in order to model, for example, the separation steps in the process of obtaining the rubber. [ABSTRACT FROM AUTHOR]

Abstract: Star polymers with different numbers and lengths of poly(tert-butyl acrylate) (PTBA) arms were obtained via atom transfer radical polymerization. Aliphatic alcohols with different number of hydroxyl groups varying from 3 to 6 and calix[4]arenes based on pyrogallol with 12 and 16 phenol groups were transformed to bromoester derivatives to prepare multifunctional ATRP initiators used as the cores of the stars. The star polymers were characterized by GPC with refractive index, multiangle laser light scattering and viscosimetric detectors. The molar masses of the stars reached 70,000g/mol and the molar mass dispersities did not exceed 1.2. To elucidate the compact structure of the stars, their true molar masses were determined by GPC with triple detection (RI–MALLS–Visco) and compared with the apparent molar masses obtained from the calibration with linear poly(tert-butyl acrylate) standards. The intrinsic viscosities of the PTBA stars of the same molar mass decreased with the number of star arms but were always lower than the intrinsic viscosities of the analogue linear PTBA polymers. The values of the branching ratio g′ decreased with increasing number of arms indicating more compact structure of stars. The branching ratio g′ was correlated to the empirical predictions. [Copyright &y& Elsevier]

Abstract: Solubility parameter and Flory Huggins interaction parameter of a triblock SBES have been obtained from intrinsic viscosity measurements. The solubility of the block copolymer in all solvents (methyl-cyclohexane, cyclohexane, cyclopentane, toluene and benzene) was found good except in the case of n-hexane. The results obtained are similar to other found in literature for SBR and SBS rubbers, and indicate that cyclohexane and cyclopentane and methylcyclohexane are the most compatible solvents for this kind of polymer. [Copyright &y& Elsevier]

Abstract: The miscibility of polystyrene/brominated polystyrene blends (PS/PBrS) was investigated by using dilute-solution viscometry (DSV) method. The intrinsic viscosity and the viscometric parameters of this system have been determined at 20±0.1°C for prepared several PS/PBrS compositions (85/15, 75/25, 50/50, 25/75, 10/90). The binary systems were prepared in chloroform at five different concentrations; 0.15, 0.30, 0.60, 0.90, 1.20g100ml−1. The miscibility criteria on the basis of the sign of Δ[η] m , Δb and Δb′, which are based on the difference between experimental and ideal values of [η] m , and b m were calculated by applying the Garcia et al., Catsiff–Hewett and Krigbaum–Wall theoretical equations. The thermodynamic parameter, α, modified thermodynamic parameter, β, and interaction parameter, μ, were also estimated. The data obtained from the viscometry studies showed that the examined blends were immiscible in all the compositions range besides the composition (10/90). The results from the DSV method are correlated with the miscibility data obtained for the same blend by differential scanning calorimetry (DSC) find. [Copyright &y& Elsevier]

Abstract: The intermolecular interactions and miscibility behavior between poly(ether imide) (Ultem®1000) and a copolyester of bisphenol-A with a mixture of terephthalic and isophthalic acid (Ardel®D-100) in compositions of 100/0, 80/20, 60/40, 40/60, 20/80 and 0/100 have been investigated in dilute solutions in chloroform. An Ubbelohde-type home-made viscometer was used to determine the specific viscosities of the blends in a constant temperature bath. Several viscosity interaction parameters used as the criteria of miscibility were determined from viscosity measurements. The parameters suggested that Ultem®1000 and Ardel®D-100 were miscible. The miscibility of the polymers was confirmed by the results of differential scanning calorimetry measurements. [Copyright &y& Elsevier]

Abstract: The viscosity behavior of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), brominated polystyrene (PBrS) and their blends at several compositions (25/75, 50/50, 75/25, 85/15) has been studied. The miscibility of this polymer system was investigated on the basis of the sign of the criteria Δb, α, ΔK, μ, and Δ[η] determined by viscosity. These investigations indicate that PPO/PBrS is miscible at the compositions of (75/25), (85/15) and completely immiscible at the compositions of (25/75), (50/50) in chloroform at 20°C. Results from viscometry match very well those of DSC results cited in the literature. [Copyright &y& Elsevier]

Abstract: Anthraquinone derivatives have been prepared and investigated as photo-stabilizers for rigid PVC by measuring the extent of weight loss (%), the amount of gel formation as well as the intrinsic viscosity of the soluble fractions of the degraded polymer. The results indicated a reasonable stabilizing effect of these derivatives compared with UV-commercially used stabilizers. A synergistic effect is achieved when the anthraquinone derivatives are mixed with UV-absorbers in a weight ratio of 75% of investigated organic stabilizer and 25% of reference stabilizer. A probable radical mechanism is proposed to account for the stabilizing action of the organic investigated materials. [Copyright &y& Elsevier]

Abstract: Hydrophobically modified ethoxylated urethanes (HEUR) associative copolymers are prepared through the hydrophobic modification of polyethylene glycol based polyurethanes. These types of thickeners are categorized as anionic associative thickeners. To investigate the effect of structure of the hydrophobic groups on the thickening properties, three different hydrophobic groups were selected. These groups were comprised of cetyl alcohol (16 carbons), dodecyl alcohol (12 carbons) and a cyclic group such as cyclo hexanol. These functional groups were substituted on the identical prepolymers made from H12MDI and polyethylene glycol. Here, three different urethane associative polymers containing hydrophobic segments and different hydrophobic groups were synthesized. The viscoelastic characteristics of all the samples were determined using a cone and plate rheometer. The viscosities of the examined HEUR samples showed both Newtonian and non-Newtonian behaviours (shear thinning and thickening) for the explored shear rates window. The steady shear viscosity results were interpreted using the theories by Raspaud [Macromolecules 27 (1994) 2956] and Semenov [Macromolecules 28 (1995) 1066]. The Cox–Merz rule happened to be applicable to these systems for the various hydrophobic ends and concentrations at lower shear rates indicating typical associative polymer behaviour. The cyclic end groups did not show viscoelasticity for the frequencies window explored. The zero shear viscosity increased by almost two orders of magnitude from HEUR-cyc to HEUR-dod and by four orders of magnitude from HEUR-cyc to HEUR-cet. The intermediate shear thickening was only observed for the concentrated HEUR-cet samples. [Copyright &y& Elsevier]

Fundamental properties of polymethyl acrylate solutions were examined: the reasonable Houwink–Mark–Sakurada relations and the theta temperature (θ) were determined to be 5 °C in toluene. Further, the measurements of intrinsic viscosity for polymethyl acrylate solutions as a function of temperature yielded a thermal transition due to a conformation change at 56 ± 1 °C, irrespective of molecular weight and solvent. An application of the two-parameter theory to such a transition gave a stepwise change of the short-range interaction: K×102=9.5 below 50 °C and 10.3 above 60 °C. This conformation transition is explained on the basis of the steric hindrance of the planar substituent to the main chain above 60 °C. [Copyright &y& Elsevier]

The copolymerizations of ethylene glycol dimethacrylate (EGDM) with α-ethyl β-N-(α′-methylbenzyl) itaconamates (RS- and S-EMBIs) derived from (RS)- and (S)-α-methylbenzylamines were conducted at 70 and 80 °C in benzene using dimethyl 2,2′-azobisisobutyrate (MAIB) of high concentration as initiator. The copolymerization of EGBM (0.20 mol/l) and RS-EMBI (0.50 mol/l) with MAIB (0.50 mol/l) proceeded homogeneously without any gelation in benzene to give benzene-soluble copolymer in a yield of 55% based on the total weight of EGDM, RS-EMBI and MAIB. The copolymer was soluble in acetone, ethyl acetate, chloroform, tetrahydrofuran (THF), toluene, N,N-dimethylformamide and insoluble in n-hexane, methanol, dimethyl sulfoxide, and water. The copolymerization system involved ESR-observable propagating radicals derived from EGDM and RS-EMBI, of which the total concentration increased with time in spite of the homogeneous system. The copolymer consisted of EGDM unit (25 mol%), RS-EMBI unit (45 mol%), and methoxycarbonylpropyl group as MAIB-fragment (30 mol%). Such a large number of initiator fragments were incorporated into the copolymer as terminal groups through initiation and primary radical termination, leading to a conclusion that the copolymer was of hyperbranched structure (initiator-fragment incorporation radical copolymerization). Radius of gyration (Rg) and Mw of the copolymer by light scattering measurements in THF were 17.8 nm and 7.7 × 105, respectively. Comparison of these values with those (Rg=27.6 nm and Mw=2.9×105) of linear polystyrene also supported the above conclusion. Reflecting the compact hyperbranched structure, the intrinsic viscosity ([η]) of the copolymer was very low, [η]=0.075 dl/g at 25 °C in THF. The individual copolymer molecules were observed as a nanoparticle by TEM. The copolymerization of EGDM and S-EMBI with MAIB in benzene also gave similar results. [Copyright &y& Elsevier]

Effects of the polyanion synthesis conditions and composition on the viscometric behavior of poly(sodium 2-acrylamido-2-methylpropanesulfonate) (PAMPS) and two random copolymers, poly(sodium 2-acrylamido-2-methylpropanesulfonate-co-methylmethacrylate) (PAMPSMM) and poly(sodium 2-acrylamido-2-methylpropanesulfonate-co-tert-butylacrylamide) (PAMPSTBA), in a wide range of concentrations were reported in this paper. The experimental data obtained in salt-free aqueous solution were plotted in terms of the Fuoss and the Rao equations in order to obtain the intrinsic viscosity values. The C&ast; values obtained as the reciprocal of the intrinsic viscosity were compared with the experimentally determined values and with those calculated according to the Odijk theory. An acceptable agreement between C&ast; values obtained by different approaches was found for the PAMPS samples with high molar masses (0.83 × 106–1.4 × 106 g/mol). For the same charge density and the same concentration the reduced viscosity values were higher for PAMPSMM comparative with PAMPSTBA indicating a higher chain extension of the former copolymer. [Copyright &y& Elsevier]

[Display omitted] • NDMM-OH(aq) was used for the first time to dissolve cellulose. • MCC 3 wt% could be dissolved in 1-2M NDMM-OH(aq) with maximum dissolution of 7 wt%. • Two different pulps showed clear microscopy images with traces of fiber ballooning. • SEC and NMR showed high stability of cellulose solutions over refrigeratin. • DLS indicated molecular dissolution of majority of cellulose. N,N -dimethylmorpholinium hydroxide was synthesized and its ability to dissolve microcrystalline cellulose and pulp was assessed for the first time. Microscopy and UV–Vis measurements showed that dissolution occurred over a range of 1–2 M concentration of the solvent and a maximum solubility of 7 wt% microcrystalline cellulose could be achieved. The stability of cellulose solutions was evaluated by size exclusion chromatography, which did not detect degradation to any noticeable extent. This observation was further confirmed by 13C NMR measurements. Finally, DLS studies confirmed that most of the cellulose was molecularly dissolved, with intrinsic viscosity values indicating cellulose chains expansion in this solvent. [ABSTRACT FROM AUTHOR]

• PEF copolymers were synthesized in the presence of an aliphatic polycarbonate diol, PPeHC. • The materials were "randomnized" and amorphous due to ester-carbonate exchange reaction. • The material properties can be tuned from thermoplastics to elastomers with the composition. • The thermoplastics possess PET-comparable mechanical but better CO 2 barrier properties. • The thermoplastic elastomers possess excellent gas barrier performance as well as high strength. Poly(ethylene 2,5-furandicarboxylate) (PEF) is a very promising biobased polymer possessing very high mechanical strength, rigidity and gas barrier performance. But its poor ductility and toughness may limit its applications. In this study, PEF-based copolymers with high intrinsic viscosity were successfully synthesized via melt polycondensation of dimethyl 2,5-furandicarboxylate (DMFD) and ethylene glycol in the presence of a copolycarbonate diol (PPeHC diol) as produced from 1,5-pentylene diol (PeDO), 1,6-hexylene diol (HDO) and dimethyl carbonate, and characterized with 1H NMR, 13C NMR, DSC, TGA, tensile, impact and gas barrier testing. The products were "randomnized" as a result of ester-carbonate exchange reaction occurring along melt polycondensation, and therefore became amorphous copolymers possessing composition-dependent physico-mechanical properties which can be tunable from rigid-to-ductile thermoplastics to thermoplastic elastomers. Particularily, the copolymers with φ PPeHC of 25 wt% and 30 wt% are thermoplastics possessing greatly improved ductility (elongation at break up to 194%) and CO 2 barrier performance higher than poly(ethylene terephthalate) (PET; BIF CO2 3.6–2.8), and retaining high tensile modulus (2.2–1.9 GPa) and yielding strength (69–58 MPa) comparable to the bottle-grade PET. In comparison, the copolymer with φ PPeHC of 40 wt% behaves as a high performance thermoplastic elastomer with excellent gas barrier performance as well as high tensile strength (23 MPa). [ABSTRACT FROM AUTHOR]