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For a single, intense 7 μm linearly polarized laser pulse, we found that the branching ratio for the fragmentation of ClCHO+ → Cl + HCO+ , H + ClCO+ , HCl+ +CO depended strongly on the orientation of the molecule (J. Phys. Chem. Lett. 2012, 3 2541). The present study explores the possibility of controlling the branching ratio for fragmentation by using two independent pulses with different frequencies, alignment and delay. Born-Oppenheimer molecular dynamics simulations in the laser field were carried out with the B3LYP/6-311G(d,p) level of theory using combinations of 3.5, 7 and 10.5 μm sine squared pulses with field strengths of 0.03 au (peak intensity of 3.15×1013 W/cm2 ) and lengths of 560 fs. A 3.5 μm pulse aligned with the C-H bond and a 10.5 μm pulse perpendicular to the C-H bond produced a larger branching ratio for HCl+ +CO than a comparable single 7 μm pulse. When the 10.5 μm pulse was delayed by one quarter of the pulse envelope, the branching ratio for the high energy product, (HCl+ +CO 73%) was a factor of three larger than the low energy product (Cl + HCO+ , 25%). By contrast, when the 3.5 μm pulse was delayed by one quarter of the pulse envelope, the branching ratio was reversed (HCl+ +CO 38%; Cl + HCO+ , 60%). Continuous wavelet analysis was used to follow the interaction of the laser with the various vibrational modes as a function of time. © 2018 Wiley Periodicals, Inc.

Biodegradable supramolecular polymers (SMPs) are synthesized by the end-functionalization of poly(lactide)-block-poly(δ-valerolactone)-block-poly(lactide) (PLA-PVL-PLA) triblock copolymers with 2-ureido-4[1H]-pyrimidinone (UPy) self-complementary quadruple hydrogen-bonding unites. The end-functionalized PLA-PVL-PLA copolymers exhibit the typical characteristics of thermoplastic elastomers. Thermal, crystallization behavior, crystalline structure and properties of SMPs can be adjusted by changing the length and stereostructure of PLA blocks. The UPy groups retard the crystallization of PLA and PVL blocks, the crystallization of PVL blocks is also depressed by the increasing PLA blocks. Tensile test reveals that the prepared SMPs presents excellent mechanical properties, DMA results indicate that the heat resistance of L-SMPs is better than that of DL-SMPs. Shape memory property of SMPs was also studied, found that recovery ratio of SMPs with PDLLA blocks can reach 100%. The recovery ratio of L-SMPs was depressed as the crystallizable PLLA blocks increase. This study has systemically investigated that effect of the composition, stereostructure, and crystallizability of PLA blocks on the properties of supramolecular polymers, which would provide potential approaches to synthesize the biodegradable supramolecular polymers with tunable properties.

In this study, several asymmetric poly(L-lactide)/poly(D-lactide) (PLLA/PDLA) blends were prepared by adding small amounts of PDLA with different structures into linear PLLA matrix. The effect of PDLA on rheological behavior, crystallization behavior, nucleation efficiency and spherulite growth of PLLA was investigated. Rheological results indicated that PLLA/PDLA blends showed solid-like viscoelastic behavior at low temperature ( PLLA/L-PDLA > PLLA/3PDLA > PLLA/4PDLA. No-isotherm and isotherm crystallization results indicated that the crystallization capacity of PLLA/PDLA blends was strongly related to the PDLA structure, crystallization temperature and thermal treatment temperature. Furthermore, the dimension of crystal growth during isotherm crystallization presented the obvious dependent on the PDLA structure. The nucleation efficiency of sc-crystallites in the blends and spherulite density during isothermal crystallization were also studied. Nucleation efficiency of sc-crystallites in the PLLA/S-PDLA blends showed the obvious dependent on thermal treatment temperature with respect to PLLA/L-PDLA, and nucleation efficiency sc-crystallites in the PLLA/S-PDLA blends first decreased and then increased as the thermal treatment temperature increased. Spherulite density of PLLA/PDLA blends was also related to thermal treatment temperature and the PDLA structure. This study has discussed the temperature dependence of the stereocomplex networks between PLLA and PDLA with different structure, and then its consequential influence on rheology and crystallization capacity of PLLA, which would provide the theoretical direction for PLA processing. Copyright © 2016 John Wiley & Sons, Ltd.

For forecasting nonstationary and nonlinear energy prices time series, a novel adaptive multiscale ensemble learning paradigm incorporating ensemble empirical mode decomposition (EEMD), particle swarm optimization (PSO) and least square support vector machines (LSSVM) with kernel function prototype is developed. Firstly, the extrema symmetry expansion EEMD, which can effectively restrain the mode mixing and end effects, is used to decompose the energy price into simple modes. Secondly, by using the fine-to-coarse reconstruction algorithm, the high-frequency, low-frequency and trend components are identified. Furthermore, autoregressive integrated moving average is applicable to predicting the high-frequency components. LSSVM is suitable for forecasting the low-frequency and trend components. At the same time, a universal kernel function prototype is introduced for making up the drawbacks of single kernel function, which can adaptively select the optimal kernel function type and model parameters according to the specific data using the PSO algorithm. Finally, the prediction results of all the components are aggregated into the forecasting values of energy price time series. The empirical results show that, compared with the popular prediction methods, the proposed method can significantly improve the prediction accuracy of energy prices, with high accuracy both in the level and directional predictions. Copyright © 2016 John Wiley & Sons, Ltd.

Foamed polylactide (PLA), PLA–PBAT (poly (butylene adipate-co-terphathalate)) blend and their composites with CaCO3 were prepared in a batch process using supercritical carbon dioxide (CO2) at 12 MPa and 45°C. The solubility of CO2 and its diffusion patterns in different PLA samples was investigated. PLA systems had a relatively high CO2 solubility related to the carboxyl groups. CO2 desorption behaviors in PLA systems first followed the Fickian diffusion mechanism in short time and then decreased slowly to a plateau. The addition of both PBAT and CaCO3 into PLA impeded the desorption of CO2. In the presence of second phase PBAT, nanoparticles CaCO3 and dissolved CO2, the PLA crystallization behavior investigated by DSC technique was greatly changed. As the desorption time increased, the gas induced crystallinity slightly decreased in consequence of less CO2 content in each system and thus less plasticization effect. The cell morphology of foamed PLA and PLA composites showed interesting microstructure patterns. The prepared pure PLA foam exhibits a typical bimodal structure because of the foaming in both the amorphous and crystalline zones. With PBAT and CaCO3 into PLA, the composite foam presented significant increase in cell uniformity and cell density. With less CO2 content in each PLA sample, the cell structure showed interesting variation. Pure PLA foam presented transition from bimodal structure to more uniform cell structure with decreased cell density. In contract, PLA–PBAT foam show unfoamed regions because of none CO2 left in the separated PBAT phase. Copyright © 2016 John Wiley & Sons, Ltd.

There is a great challenge in regenerating osteochondral defects because they involve lesions of both cartilage and subchondral bone, which have remarkable differences in their chemical compositions and biological lineages. Thus, considering the complicated requirements in osteochondral reconstruction, a biomimetic biphasic osteochondral scaffold (BBOS) with the layer-specific release of stem cell differentiation inducers are developed. The cartilage regeneration layer (cartilage scaffold, CS) in the BBOS contains a hyaluronic acid hydrogel to mimic the composition of cartilage, which is mechanically enhanced by host-guest supramolecular units to control the release of kartogenin (KGN). Additionally, a 3D-printed hydroxyapatite (HAp) scaffold releasing alendronate (ALN) is employed as the bone-regeneration layer (bone scaffold, BS). The two layers are bound by semi-immersion and could regulate the hierarchical targeted differentiation behavior of the stem cells. Compared to the drug-free scaffold, the MSCs in the BBOS could be promoted to differentiate into both chondrocytes and osteoblasts. The in vivo results demonstrate the strong promotion of cartilage or bone regeneration in their respective layers. It is expected that this BBOS with layer-specific inducer release can become a new strategy for osteochondral regeneration.

In this study, stereocomplexed poly(lactide) (PLA) was investigated by blending linear poly(l-lactide) (PLLA) and tri-block copolymer poly(d-lactide) − (polyethylene glycol) − poly(d-lactide) (PDLA-PEG-PDLA). Synthesized PDLA-PEG-PDLA tri-block copolymers with different PEG and PDLA segment lengths were studied and their influences on the degree of sterecomplexation and non-isothermal crystallization behaviour of the PLLA/PDLA-PEG-PDLA blend were examined in detail by DSC, XRD and polarized optical microscopy. A full stereocomplexation between PLLA and PDLA-PEG4k-PDLA200 could be formed when the L/D ratio ranged from 7/3 to 5/5 without the presence of PLA homocrystals. The segmental mobility and length of both PEG and PDLA are the dominating factors in the critical D/L ratio to achieve full stereocomplexation and also for nucleation and spherulite growth during the non-isothermal crystallization process. For fixed PEG segmental length, the stereocomplexed PLA formed showed first an increasing and then a decreasing melting temperature with increasing PDLA segments due to their intrinsic stiff mobility. Furthermore, the effect of PEG segmental mobility on PLA stereocomplexation was investigated. The results clearly showed that the crystallization temperature and melting temperature of stereocomplexed-PLA kept increasing with increasing PEG segmental length, which was due to PEG soft mobility in the tri-block copolymers. However, PEG was not favourable for nucleation but could facilitate the spherulite growth rate. Both the PDLA and PEG segmental lengths in the tri-block copolymers affect the crystallinity of stereocomplexed-PLA and the stereocomplexation formation process; they have a different influence on blends prepared by solution casting or the melting method. © 2015 Society of Chemical Industry

A new pentadentate oxime has been designed to drive the preferential coordination favored by Co(I) in catalysts used for proton/water reduction. The ligand incorporates water upon metal coordination and is water soluble. This Co(III) species is doubly reduced to Co(I) and exhibits H(+) reduction activity in the presence of weak acids in MeCN and evolves H2 upon protonation suggesting that the ligand design increases catalyst effectiveness. Superior catalysis is observed in water with a turnover number (TON) of 5700 over 18 h. However, the catalyst yields Co-based nanoparticles, indicating that the solvent media may dictate the nature of the catalyst.

Four-armed star poly(l-lactide) grafted multiwalled carbon nanotubes (CNTs-g-4PLLA) were synthesized through the nucleophilic substitution reaction between 4PLLA and acryl chloride of CNTs and then characterized by transmission electron microscope, X-ray photoelectron spectroscopy, thermal gravimetric analysis (TGA), and ultraviolet visible spectrophotometer. The results indicated that 4PLLA was successfully grafted onto CNTs, and CNTs-g-4PLLA contained 37.7 wt% of 4PLLA. PLLA/CNTs-g-4PLLA nanocomposites were prepared by solution casting with different CNTs-g-4PLLA content. Rheological behavior of PLLA/CNTs-g-4PLLA nanocomposites was measured using a rheometer. The result showed that CNTs-g-4PLLA formed a network structure at percolation concentration, which improves obviously rheological properties of PLLA in the molten state. The crystallization behavior and crystal structure of the nanocomposites were comprehensive evaluated through differential scanning calorimetry, X-ray diffraction, and polarizing optical microscope. The results found that CNTs-g-4PLLA played two roles in PLLA crystallization. The addition of CNTs-g-4PLLA acted as nucleating agent and obviously accelerated the spherulites growth under percolation concentration, while it inhibited the movement of PLLA chains at above percolation concentration, resulting in the decrease of crystallinity. Thermal stability and mechanical properties of the nanocomposites were also investigated using TGA, dynamic mechanical analysis, and tensile test. These results indicated that the incorporation of CNT-g-4PLLA into the PLLA matrix improved the thermal stability, storage modulus, and tensile strength of the nanocomposites. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Microcellular foaming of poly(phenylene sulfide) (PPS) and its glass–fiber (GF) reinforced composites using supercritical CO2 as a blowing agent presents a promising approach to produce novel cellular materials with tailored microstructures. This study investigated the effects of the material composition and process conditions on the foaming behaviors and final morphologies of the microcellular foamed PPS and PPS/GF composites. The rheological and thermal properties as well as the saturation and desorption behaviors of CO2 in the pure PPS and PPS/GF composites were also detailedly discussed. The results show that microcellular foams with various relative densities, cell sizes, cell-size distributions, and cell densities can be attained by tailoring the fiber content and key process parameters. At low foaming temperatures below the cold crystallization temperature, the microcellular foamed PPS and PPS/GF composites both present a unimodal cell-size distribution. At elevated temperatures, the generated crystalline superstructures including spherulites in the polymer matrix and transcrystals around the GF will cause a secondary heterogeneous cell nucleation. This leads to the observations of bimodal and trimodal cell-size distributions in the pure PPS and the PPS/GF composites, respectively. The mechanisms for the solid-state foaming behaviors of pure PPS and PPS/GF composites have been illustrated by establishing theoretical models. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Poly(L-lactide) (PLLA) composites with TiO2-g-poly(D-lactide) (PDLA), which was synthesized by surface-initiated opening ring polymerization with TiO2 as initiator and Sn(Oct)2 as catalyst, were prepared by solution casting. The synthesized TiO2-g-PDLA was characterized by transmission electron microscope (TEM) and dynamic laser scattering (DLS), showing larger size corresponding to that of TiO2. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) measurements were further carried out and indicated that PDLA was grafted onto TiO2 through covalent bond. For PLLA/TiO2-g-PDLA composites, the stereocomplex crystallites were formed between PDLA grafted on the surface of TiO2 and the PLLA matrix, which was determined by FT-IR, differential scanning calorimetry (DSC), and X-ray diffractometer (XRD). The influence of stereocomplex crystallites on the rheological behavior of PLLA/TiO2-g-PDLA was investigated by rheometer, which showed greater improvement of rheological properties compared to that of PLLA/TiO2 composites especially with a percolation content of TiO2-g-PDLA between 3 wt%–5 wt%. The crystallization and melting behavior of PLLA/TiO2-g-PDLA composites were studied by DSC under different thermal treatment conditions. The formed PLA stereocomplex network acted as nucleating agents and a special interphase on the functional surface of TiO2, which resulted in imperfect PLLA crystal with lower melting temperature. When the thermal treatment was close to the melting temperature of PLA stereocomplex, the crystallinity approached to the maximum. The isothermal crystallization study by polarizing microscope (POM) indicated that stereocomplex network presented stronger nucleation capacity than TiO2-g-PDLA. Copyright © 2015 John Wiley & Sons, Ltd.

Engineering living tissues that simulate their natural counterparts is a dynamic area of research. Among the various models of biological tissues being developed, fiber-shaped cellular architectures, which can be used as artificial blood vessels or muscle fibers, have drawn particular attention. However, the fabrication of continuous microfiber substrates for culturing cells is still limited to a restricted number of polymers (e.g., alginate) having easy processability but poor cell-material interaction properties. Moreover, the typical smooth surface of a synthetic fiber does not replicate the micro-and nanofeatures observed in vivo, which guide and regulate cell behavior. In this study, a method to fabricate photocrosslinkable cell-responsive methacrylamide-modified gelatin (GeIMA) fibers with exquisite microstructured surfaces by using a microfluidic device is developed. These hydrogel fibers with microgrooved surfaces efficiently promote cell encapsulation and adhesion. GeIMA fibers significantly promote the viability of cells encapsulated in/or grown on the fibers compared with similar grooved alginate fibers used as controls. Importantly, the grooves engraved on the GeIMA fibers induce cell alignment. Furthermore, the GeIMA fibers exhibit excellent processability and could be wound into various shapes. These microstructured GeIMA fibers have great potential as templates for the creation of fiber-shaped tissues or tissue microstructures

Functionalized carbon nanotubes (F-CNTs) were synthesized through the nucleophilic substitution reaction between four-armed star poly(d-lactide) (4PDLA) and acryl chloride of carbon nanotubes and were characterized using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis. The results indicated that the 4PDLA was successfully grafted onto carbon nanotubes, and it contained 45.5 wt% of 4PDLA. Poly(l-lactide) (PLLA) nanocomposites with different F-CNTs content were prepared by solution casting. Optical microscopy and scanning electron microscopy results showed that F-CNTs were uniformly dispersed in the nanocomposites. Crystallization behavior and crystal structure of PLLA nanocomposites were investigated using differential scanning calorimetry, polarizing microscope and X-ray diffraction. The results found that poly(lactide) stereocomplex crystal could be formed between PLLA and F-CNTs. F-CNTs played different roles in the process of solution casting and melting crystallization. Polarizing microscope also revealed that crystallization temperature had a significant effect on the nucleation and spherulites growth of PLLA. Thermal stability and mechanical properties of the nanocomposites were also investigated by thermogravimetric analysis, dynamic mechanical analysis and tensile testing. These results demonstrated that the addition of F-CNTs obviously improved thermal stability and tensile strength of PLLA. The results showed that PLLA/F-CNTs would have potential values in engineering fields. Copyright © 2015 John Wiley & Sons, Ltd.

The Fe3O4/poly(lactide-co-glycolide) (PLGA) composites were prepared via a surface grafting technique. Initially, the poly(lactic acid) oligomer was synthesized and surface-grafted to Fe3O4 nanoparticles. Then, the grafted Fe3O4 particles were compounded with PLGA matrix by a simple solution blending method. The grafted Fe3O4 particles presented enhanced compatibility with PLGA matrix and the composites indicated enhanced dynamic mechanical performance. Electrochemical tests showed that the Fe3O4/PLGA composite coating can help improve the impedance of magnesium samples by 100–300%, and the impedance of the metal may be tunable by altering the components ratio of LA/GA within PLGA matrix. The composites may have potential application for magnesium alloy used in degradable medical implants. POLYM. COMPOS., 2014. © 2014 Society of Plastics Engineers

A "sticker-like" PLGA nanosheet with microgrooved patterns is developed through a facile combination of spin coating and micropatterning techniques. The resulting microgrooved PLGA nanosheets can be physically adhered on flat or porous surfaces with excellent stability in aqueous environments and can harness the spatial arrangements of cells, which make it a promising candidate for generating biomimic periosteum for bone regenerative applications.

A novel superabsorbent was prepared by the copolymerization reaction between multiwalled carbon nanotubes (MWCNTs)–xylan composite and poly(methacrylic acid) (PMAA) in the presence of N,N′-methylenebisacrylamide as cross-linker and the redox initiation system (NH)4S2O8-anhydrous Na2SO3 as initiator for adsorbing methylene blue (MB) from aqueous solution. First, covalent modification of MWCNTs with a natural polymer xylan was achieved by the nucleophilic substitution reaction. The obtained xylan modified MWCNTs–xylan composite was characterized by transmission electron microscope, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer, and thermal gravimetric analysis. The results indicated that the hydroxyl groups of xylan participated in the formation of MWCNTs–xylan composite, and MWCNTs–xylan composite contained 32% xylan and about four molecule chains of xylan were grafted onto 5,000 carbon atoms of MWCNTs sidewalls. Subsequently, a novel superabsorbent based on MWCNTs–xylan composite and PMAA was prepared and characterized by Fourier transform infrared spectroscopy, scanning electron microscope, and swelling test. The results proved that superabsorbent was successfully prepared by copolymerization reaction and found that the superabsorbent evidently presented three-dimensional network structure. Swelling process of superabsorbent complied with the Fick's law. Adsorption property of superabsorbent for MB was also systematically studied by investigating these parameters, such as superabsorbent dosage, initial MB concentration, contact time, ion strength, and pH. The superabsorbent presented a higher adsorption capacity and removal rate for MB. The adsorption data were fitted by Langmuir, Freundlich isotherm models, and four adsorption kinetic models. Freundlich isotherm model better fitted the equilibrium data than Langmuir, and adsorption kinetics could be well described by pseudo-second-order kinetic and intraparticle diffusion. These results indicated that the superabsorbent can be used as an efficient absorbent for removal of MB from aqueous solution. POLYM. COMPOS., 35:1516–1528, 2014. © 2013 Society of Plastics Engineers

Elaborating a bone replacement using tissue-engineering strategies for bone repair seems to be a promising remedy. However, previous platforms are limited in constructing three-dimensional porous scaffolds and neglected the critical importance of periosteum (a pivotal source of osteogenic cells for bone regeneration). We report here an innovative method using the periosteum as a template to replicate its exquisite morphologies onto the surfaces of biomaterials. The precise topographic cues (grooved micropatterns) on the surface of collagen membrane inherited from the periosteum effectively directed cell alignment as the way of natural periosteum. Besides, we placed the stem-cell and endothelial-cell-laden collagen membrane (pseudo-periosteum) onto a three-dimensional porous scaffold. The pseudo-periosteum-covered scaffolds showed remarkable osteogenesis when compared with the pseudo-periosteum-free scaffolds, indicating the significant importance of pseudo-periosteum on bone regeneration. This study gives a novel concept for the construction of bone tissue engineering scaffold and may provide new insight for periosteum research.

Understanding the effect of graphene on cellular behavior is important for enabling a range of new biological and biomedical applications. However, due to the complexity of cell responses and graphene surface states, regulating cellular behaviors on graphene or its derivatives is still a great challenge. To address this challenge we have developed a novel, facile route to regulate the cellular behaviors on few-layer reduced graphene oxide (FRGO) films by controlling the reduction states of graphene oxide. Our results indicate that the surface oxygen content of FRGO has a strong influ ence on cellular behavior, with the best performance for cell attachment, proliferation and phenotype being obtained in moderately reduced FRGO. Cell performance decreased significantly as the FRGO was highly reduced. Moderate performance was found in non-reduced pure graphene oxide and control glass slides. Our results highlight the important role of surface physicochemical characteristics of graphene and its derivatives in their interactions with biocomponents, and may have great potential in enabling the utility of graphene based materials in various biomedical and bioelectronic applications.

Microcellular foaming of poly(phenylene sulfide)/poly(ether sulfones) (PPS/PES) blends presents a promising approach to produce high-performance cellular materials with tailored microstructures and enhanced properties. This study investigated the effects of multiphase blend composition and process conditions on the foaming behaviors and final cellular morphology, as well as the dynamic mechanical properties of the solid and microcellular foamed PPS/PES blends. The microcellular materials were prepared via a batch-foam processing, using the environment-friendly supercritical CO2 (scCO2) as a blowing agent. The saturation and desorption behaviors of CO2 in PPS/PES blends for various blend ratios (10 : 0, 8 : 2, 6 : 4, 5 : 5, 4 : 6, 2 : 8, and 0 : 10) were also elaborately discussed. The experimental results indicated that the foaming behaviors of PPS/PES blends are closely related to the blend morphology, crystallinity, and the mass-transfer rate of the CO2 in each polymer phase. The mechanisms for the foaming behaviors of PPS/PES blends have been illustrated by establishing theoretical models. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42634.

A series of thermal insulation, acoustic absorption isocyanate-based lightweight polyimide (PI) foams with 4,4′-diaminodiphenyl ether (ODA) units were prepared from polyaryl polymethylene isocyanate (PAPI) and the esterification solution derived from pyromellitic dianhydride (PMDA) and ODA. The structures and properties of the PI foams prepared with different molar ratio of ODA/PMDA were investigated in detail. The results show that the ODA units have great influence on the foam properties. With the increase of the ODA units, the density decreases firstly and then increases. When the molar ratio of ODA/PMDA is 3/10, the foam reaches the minimum density (13.7 kg/m3). Moreover, with increasing the ODA units, the acoustic absorption properties increase firstly and then decrease owing to the variation of the average cell diameter of the PI foams. All PI foams show excellent thermal stability, and the 5% and 10% weight loss temperature are in the range of 250–270 °C and 295–310 °C, respectively. In addition, the PI foams present low thermal conductivity and thermal diffusivity. Furthermore, the mechanical property was also evaluated and the compressive strength of the PI foams is in the range of 33.0–45.7 kPa. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46029.

Supramolecular poly(ɛ-capolactone)/poly(lactide) alternating multiblock copolymers were prepared by UPy-functionalized poly(lactide)-b-poly(ɛ-capolactone)-b-poly(lactide) copolymers. The prepared supramolecular polymers (SMPs) exhibit the characteristic properties of thermoplastic elastomers. The stereo multiblock SMPs (sc-SMPs) were formed by blending UPy-functionalized poly(l-lactide)-b-PCL-b-poly(l-lactide) (l-SMPs) and UPy-functionalized poly(d-lactide)-b-PCL-b-poly(d-lactide) (d-SMPs) due to stereocomplexation of the PLLA and PDLA blocks. Sc-SMPs with low content of d-SMPs (≤20%) are transparent, elastic solids, while those having high d-SMPs content are opaque, brittle solids. The effects of l-SMPs/d-SMPs mixing ratios on thermal, crystallization behaviors, crystal structure, mechanical and hydrophilic properties of sc-SMPs were deeply investigated. The incorporation of UPy groups depresses the crystallization of polymer, and the stereocomplex formation accelerates the crystallization rate. The used initiator functionalized polyhedral oligomeric silsesquioxanes causes a different effect on the crystallization of PLA and PCL blocks. The tensile strength and elongation at break of ld/dd-SMPs (d represents the initiator diethylene glycol) are significantly larger than that of lp/dp-SMPs (p represents the initiator polyhedral oligomeric silsesquioxanes), and their heat resistance and hydrophilicity can be also modulated by the l-SMPs/d-SMPs mixing ratios and the different initiators. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45575.

Magnesium-based metallic glasses (MMGs) show intriguing potentials for application as implantable biomaterials owing to their disordered atomic structure, good biodegradability, low elastic modulus, high strength, and large elasticity. However, despite of all these advantages, their brittleness is their Achilles’ heel, which severely limits their application as biomedical materials. In the current study, a signifi cantly improved ductility of MMGs under bending and tensile loading through minor alloying with rare-earth element ytterbium (Yb) at an atomic concentration of 2 and 4% is reported. The enhanced ductility is attributed to the increased density of shear bands close to fracture end and larger plastic zones on the fracture surface. In comparison with that of Yb-free control, in vitro cell culture study confi rms an improved biocompatibility of MMGs alloyed with Yb as determined by MTT, live-dead, and cytoskeleton staining assays, respectively.