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The micro foaming performance, moisture resistance and dynamic viscosity of scCO2-aid glutaraldehyde/hexametaphosphate/thermoplastic tapioca starch (GA/SHMP/TOS) foams were considerably improved by proper NaOH treatment. The expansion ratio, resilience rate, dynamic viscosity values of these NaOH modified foams improved to a maximum, as the time for NaOH treatment approached a proper value. The dynamic viscosity, expansion ratio and resilience rate of the scCO2-aid GA/SHMP/TOS foams modified using 110 atm scCO2-pressure, the proper alkali treatment time, SHMP loading and varying montmorillonite (MMT) loadings improved further, as their MMT loadings approached a proper value of 2.5 part per hundred parts of tapioca starch (PHTOS). Relatively large dynamic viscosity (7.1x104 Pa·s), extremely large expansion ratio (∼75), cell density (1.1x109 cells/cm3) and/or resilience rate (∼80%) were acquired for the scCO2-aid GA/SHMP/TOS/MMT foam modified using the proper alkali treatment time and MMT loading. Thermal analyses results showed that crystallization onset temperatures and crystallization rates of scCO2-aid GA/SHMP/TOS/MMT foams modified using the proper alkali treatment time and varying MMT loadings improved to a highest value by adding 2.5 PHTOS of MMT nano-platelets. Possible reasons accounting for the considerably improved micro foaming performance of scCO2-aid GA/SHMP/TOS/MMT foams modified using the proper alkali treatment time and MMT loading are proposed in this study.

Nano-SiO2 particles have been incorporated into high-performance poly(ether ketone ketone) (PEKK) polymers to prepare satisfactory nanocomposite substrates for fifth-generation (5G) communication. Significantly lower dielectric constant (er), dielectric loss (tan δ), and linear coefficient of thermal expansion (CTE) were found for each PEKKaxSiO2y nanocomposite film series incorporated with proper loadings of nano-SiO2 particles. The dielectric characteristics measured for each PEKKaxSiO2y nanocomposite film series decreased to a minimum as the nano-SiO2 loading approached an optimum value. Satisfactory er (2.74 at 1 MHz), tan δ (0.00309 at 1 MHz), and linear CTE (~ 37 × 10−6/°C) for 5G high-speed communication were found for the nanocomposite film modified with the optimum nano-SiO2 loading of 10 wt.%. The porosity values measured for each PEKKaxSiO2y film series remained nearly zero then increased abruptly as the nano-SiO2 loading exceeded 10 wt.%. The free volume characteristics evaluated for each PEKKaxSiO2y film series increased to a maximum as the nano-SiO2 loading reached the optimum value of 10 wt.%. Possible explanations for the noticeably reduced dielectric and linear CTE characteristics found for PEKKaxSiO2y composite films are proposed.

Renewable thermoplastic starch (TPS) was modified by poly (vinyl alcohol) (PVA) with varying degrees of polymerization (DPs) or scCO2-assisted processing to prepare TPSxPVAyz or scCO2TPSxPVAyz fully biodegradable blends. The TPSxPVAyz (or scCO2TPSxPVAyz) films showed the smallest free volume characteristics and oxygen transmission rates (OTRs), as their PVA loadings approached an optimum value. The smallest free volume characteristics and OTRs evaluated for each optimal TPSxPVAyz (or scCO2TPSxPVAyz) films reduced noticeably as their DPs reduced from 2400 to 300. Considerably smaller OTRs and free volume characteristics were acquired for scCO2TPSxPVAyz films than those of corresponding TPSxPVAyz films prepared without the assistance of scCO2. An essential result is that the OTR of the optimal scCO2TPSxPVAyz film with a moisture content of 4wt% was merely 4.6 cm3/m2∙day∙atm. This OTR is as good as that of the polyvinylidene chloride oxygen barrier packaging. Dynamic mechanical relaxations and WAXD characterizations revealed that TPS and PVA are miscible, as PVA loadings were ≤ the optimum values. The enhanced oxygen barrier resistance and reduced free volume characteristics for optimal TPSxPVAyz and scCO2TPSxPVAyz films are partly ascribed to the strengthened molecular interactions between O–H groups of TPS and PVA, as they were processed with the assistance of scCO2, optimum PVA loadings or diminished DPs.

The expansion ratio, resilience rate, moisture-proof, complex dynamic viscosity and crystallization rate for scCO2-aid glutaraldehyde modified thermoplastic starch (SCaTSGA1.6) foams were substantially improved by further modification with sodium hexametaphosphate (SHP) and/or nano-silica (nano-SiO2) particles during their scCO2-assisted foaming processes. These properties of SHP modified SCaTSGA1.6 (SCaTSGA1.6SHPb and SC11TSGA1.6SHP4SiO2c) foams were further improved with increasing scCO2-pressures during their scCO2-assisted foaming processes. Extremely high expansion ratio of ~ 65 and high resilience rate of 77% of the most appropriate SC11TSGA1.6SHP4SiO20.5 foam were originally prepared using scCO2-assisted foaming processes. The significantly enhanced reliance rate found for SCaTSGA1.6SHPb and SC11TSGA1.6SHP4SiO2c foams is attributed to the better resilience of the smaller cell structures. Moreover, reaction of phosphate groups of SHP with the moisture-sensitive O–H groups of starch did occur favorably, and substantially improved the moisture-proof and complex dynamic viscosity (or melt strength) during the scCO2-assisted modification processing of SCaTSGA1.6SHPb and SC11TSGA1.6SHP4SiO2c. Thermal analyses revealed that crystallization rates and crystallization onset temperatures for SC11TSGA1.6SHP4SiO2c were substantially improved by addition of nano-SiO2 particles. This substantial increase in melt strength, higher dissolved CO2 concentrations at larger scCO2-pressures and/or higher crystallization rates for SCaTSGA1.6SHPb and/or SC11TSGA1.6SHP4SiO2c are expected to considerably enhance their nucleation rate and stability of cell structures during their scCO2-aid foaming processes. Consequently, higher expansion ratio, cell density and better reliance rate was found after the scCO2-aid foaming processes of SCaTSGA1.6SHPb and SC11TSGA1.6SHP4SiO2c foams.

Poly(lactic acid) (PLA) was thermally blended with adipate ester (AE) to enhance the toughness of PLA. All specimens which were biodegradable materials were prepared using a plasticorder. Differential scanning calorimetry and Fourier-transform infrared spectroscopy indicated that the PLA structure was looser because of the presence of the AE additive. The elongation at break and biodegradable property increased substantially with increasing amounts of AE. The results reveal that excessive amounts of plasticizer would cause the exudation of AE from the PLA/AE composites, which was ascribed to the plasticizer migration phenomenon.

Novel ultrahigh molecular weight polyethylene (UHMWPE)/cellulose nanofiber (CNF) (F100CNFy) and UHMWPE/modified cellulose nanofiber (MCNFx) (F100MCNFxy) as-prepared nanocomposite fibers were successfully prepared by gel-spinning F100CNFy and F100MCNFxy gel solutions, respectively. CNF nanofillers with a specific surface area at 120 m2/g and a nanofiber diameter of 20 nm were successfully prepared by proper acid hydrolysis of cotton fibers using sulfuric acid solution. MCNFx nanofillers were prepared by grafting various contents of maleic anhydride grafted polyethylene (PEg-MAH) onto CNF nanofillers. The ultimate σf value of the best-prepared F100MCNFxy drawn fiber reached 4.5 GPa, which is about 67% higher than that of the UHMWPE drawn fiber prepared without the addition of any nanofiller. To understand the interesting ultradrawing, orientation, and tensile properties of F100CNFy and F100MCNFxy fibers, Fourier transform infrared, transmission electron microscopic analyses of the CNF and MCNFx nanofillers, and scanning electron microscopic analyses of profile surfaces of the etched drawn fibers were performed. This is the first work in this area of research wherein very small amounts of MCNFx nanofillers prepared from cotton fibers were efficiently used as nucleating agents to enhance the ultradrawing and ultimate tensile properties of F100MCNFxy fibers. Copyright © 2016 John Wiley & Sons, Ltd.

Fully bio-based polyamide 1010 (PA1010) was successfully melt-blended with poly (vinyl alcohol) (PVA03, PVA05, PVA08 and PVA14) to prepare PA1010xPVAzy blends. The PA1010xPVA03y, PA1010xPVA05y, PA1010xPVA08y and PA1010xPVA14y films demonstrated the lowest oxygen transmission rates (OTR), free volume fraction (Fv), mean volume of the free volume holes (Vf) and mean number of free volume holes per unit volume (I3) values, when the PVA concentration in each PA1010xPVAzy series reached a corresponding critical value of 22.5, 20, 17.5 and 12.5 wt%, respectively. OTR, Fv, Vf and I3 values obtained for the best PA101087.5PVA1412.5, PA101082.5PVA0817.5, PA101080PVA0520 and PA101077.5PVA032.25 films reduced gradually as the degree of polymerization of PVA reduced. The results of dynamical mechanical and other experimental characterizations demonstrated that PA1010 and PVA are compatible to some extent, when the PVA are ≤ the corresponding critical concentration. The significantly enhanced oxygen permeation resistance and free volume characteristics for optimal PA1010xPVAzy films is at least partly due to the improved hydrogen-bonded molecular interactions between PA1010 C=O groups and PVA O-H groups.

Novel ultra-high molecular weight polyethylene (UHMWPE)/nanoalumina (F100Ay), UHMWPE/acid-treated nanoalumina (F100Aox%-8-y) and UHMWPE/functionalized nanoalumina (F100Aox%-81PEg-MAHxy) as-prepared nanocomposite fibers were prepared by gel-spinning processes. The rod-like features of the original nanoalumina fillers were significantly etched into broken/shorter nanorods and/or shreds by oxalic acid solutions as their concentrations and/or treating time increased. As evidenced by Fourier transform infrared and transmission electron microscopy analysis, PEg-MAH molecules were successfully grafted onto acid-treated nanoalumina fillers through the reaction of the hydroxyl groups of nanoalumina fillers with the maleic anhydride groups of PEg-MAH molecules during their modification processes. The specific surface areas of each Aox%-81PEg-MAHxy functionalized nanoalumina filler reached a maximum value (≧470 m2/g), as the weight ratios of PEg-MAH to acid-treated nanoalumina approached the optimal value at 8. The achievable draw ratio ( Dra) values of F100Ay, F100Aox%-8-y and/or F100Aox%-81PEg-MAHxy as-prepared fibers approach a maximal value as the original, acid-treated and/or functionalized nanoalumina contents reach the optimal values at 0.1, 0.1 and 0.075 phr, respectively, in which, the maximal Dra values obtained for F100Aox%-81PEg-MAHx0.075 as-prepared fiber specimens are significantly higher than those of the F100A0.1 and F100Aox%-8-0.1 drawn fiber specimens prepared at the same draw ratios. Moreover, the maximal Dra values obtained for F100Aox%-81PEg-MAHx0.075 as-prepared fibers reached another maximal value as the functionalized nanoalumina fillers were modified using the optimal weight ratio of PEg-MAH to acid-treated nanoalumina at 8. Further investigation revealed that excellent orientation and tensile properties of the UHMWPE nanocomposite fibers can be obtained by ultradrawing the F100Aox%-81PEg-MAHxy as-prepared fibers with proper amounts of well-dispersed functionalized nanoalumina fillers.

The improvement of the ultradrawing and ultimate tensile properties of high performance fibers is the most critical and challenging for applications of high performance fibers, such as ultra high molecular weight polyethylene (UHMWPE) fibers. This paper aims to improve the ultradrawing and ultimate tensile properties of UHMWPE fibers by incorporating very small amounts of nanofillers during the gel spinning process of UHMWPE fibers. Activated nanocarbon (ANC), acid treated activated nanocarbon (ATANC) and functionalized activated nanocarbon (FANC) prepared by grafting maleic anhydride polyethylene onto ATANC, were added into the UHMWPE fibers as effective nucleation nanofillers with specific surface areas higher than 1000 m2 g−1. This is the first work where ANC, ATANC and FANC were used as reinforced or functional additives in UHMWPE composite fibers to enhance their ultradrawing and/or ultimate tensile properties. The experimental results show that the maximum achievable draw ratio obtained for the best prepared UHMWPE/FANC fiber reaches 398 and the ultimate tensile strength (σf) of the best prepared UHMWPE/FANC drawn fiber reaches around 7.8 GPa, when the mass fraction of FANC is 0.075 phr. They are the highest draw ratios and σf values obtained so far for UHMWPE/nanofiller composite fibers reported in the literature.

This paper describes sodium hexametaphosphate (SHMP)‐modified thermoplastic starch (TPS) resins (scCO₂TPS₁₀₀SHMPₓ) gelatinized and/or modified with the aid of supercritical carbon dioxide (scCO₂). TPS and scCO₂TPS₁₀₀SHMPₓ exhibit considerably higher melt flow rates, moisture resistance, and initial and retention tensile strength values than TPS and TPS₁₀₀SHMPₓ prepared using conventional atmospheric pressure. Only Vₕ‐type crystals are found in conditioned scCO₂TPS₁₀₀SHMPₓ, which show significantly lower melting temperatures (≈19 °C) than the corresponding conditioned TPS₁₀₀SHMPₓ. Relative to TPS₁₀₀SHMPₓ, conditioned scCO₂TPS₁₀₀SHMPₓ show a weaker hydrogen bonding network among the hydroxyl groups in the amylopectin chains and considerably less retrogradation. The loosely hydrogen‐bonded hydroxyl groups found in conditioned scCO₂TPS₁₀₀SHMPₓ can be replaced with stronger hydrogen bonds involving the phosphate groups of SHMP through the proper modification of scCO₂TPS₁₀₀SHMPₓ.

This paper represents the first report of polyvinyl alcohol (PVA) modified TPS resins (scCO2TPSxPVA05y), gelatinized and/or modified with the aid of supercritical carbon dioxide (scCO2). The melt flow rate, initial and retention values of tensile strength (σf) of scCO2TPSxPVA05y prepared with the aid of both scCO2 and PVA05 were considerably higher than those of the corresponding scCO2TPS prepared using scCO2 fluid and/or TPSxPVA05y materials prepared in the conventional way. The moisture contents of conditioned scCO2TPSxPVA05y were considerably lower than those of the corresponding scCO2TPS and TPSxPVA05y aged for the same amounts of time. Conditioned scCO2TPSxPVA05y exhibited only Vh-type crystals with melting temperatures ∼ 40 °C and ∼ 20 °C lower than those of corresponding conditioned TPS and TPSxPVA05y, respectively. In comparison to TPS and TPSxPVA05y, more dissociated amylopectin chains with loosely hydrogen-bonded −OH groups and significantly less retrogradation was obtained for conditioned scCO2TPS and scCO2TPSxPVA05y, respectively.

Oxygen transmission rates and free volume properties (i.e. average volumes of free-volume-cavities (Vf), mean number of the free volume cavities per unit volume (I3) and fractional free volume (Fv)) values of bio-based polyamide 612 (PA612)/poly(vinyl alcohol) (PVA) (i.e. PA612xPVA03y, PA612xPVA05y, PA612xPVA08y and PA612xPVA14y) blend films were reduced to a minimum value, when their PVA content reached corresponding optimal values of 25, 20, 15 and 10 wt%, respectively. The minimum oxygen transmission rate, Vf, I3 and Fv value obtained for the best PA61290PVA1410, PA61285PVA0815, PA61280PVA0520 and PA61275PVA0325 bio-based blown films reduced considerably with decreasing PVA degrees of polymerization. As evidenced by the results of dynamical mechanical analysis, differential scanning calorimetry, wide angle X-ray diffraction and Fourier transform infrared spectroscopic experiments, PA612 and PVA are miscible to some extent at the molecular level when their PVA contents are ≤ the corresponding optimal values. The significantly improved oxygen barrier and free volume properties for the PA612xPVAzy blend films with optimized compositions is at least in part to the enhanced intermolecular interactions between PA612 carbonyl groups and PVA hydroxyl groups.

The strength retention and moisture resistant properties of thermoplastic starch (TPS) resins were significantly enhanced by modifying with proper amounts of citric acid (CA) (i.e. TPS100CAx specimens) or by melt-blending with poly(lactic acid) (PLA) (i.e. (TPS100CA0.1)xPLAy specimens). In contrast to the distinguished retrogradation effect found for all conditioned TPS specimens, one can barely find any recrystallized starch crystals in TPS100CAx and/or (TPS100CA0.1)xPLAy specimens maintained at 20 °C/50% RH for less than 42 days. The tensile/impact strength retention values of properly prepared conditioned TPS100CA0.1 and (TPS100CA0.1)30PLA70 specimens were equivalent to 1.5 MPa/0.28 KJ/m2 and 41.8 MPa/1.63 KJ/m2, respectively, which were more than 4/4 times and 105/23 times higher than those of corresponding TPS specimens maintained at 20 °C/50% RH for 70 days. In comparison with conditioned TPS specimens, significantly less and shorter drawn debris were found on the fracture surfaces of the corresponding conditioned TPS100CA0.1 and (TPS100CA0.1)30PLA70 specimens with the same amounts of conditioned time. As revealed by Fourier transform infrared spectroscopy, Solid-state 13C Nuclear Magnetic Resonance analyses, disruption of intra and interhydrogen-bondings within starch molecules did occur after addition of small amounts of CA during the modification processes of TPS100CAx specimens. The relatively unchanged in retrogradation effect, significantly less drawn debris and considerable improvement in moisture resistant and/or strength retention properties of the conditioned TPS100CAx and/or (TPS100CA0.1)xPLAy specimens is most likely due to the efficient hydrogen-bonding CA molecules with the moisture-absorbing hydroxyl (free or hydrogen-bonded) of starch molecules that prohibits moisture absorption during their conditioning processes.

Ultradrawing and ultimate tensile properties of ultrahigh molecular weight polyethylene (UHMWPE) composite fibers were successfully improved by the addition of nanoalumina (NAL), acid treated nanoalumina (ATNAL), and/or functionalized nanoalumina (FNAL). As evidenced by FTIR and TEM analyses, maleic anhydride grafted polyethylene (PEg-MAH) molecules were successfully grafted onto ATNAL fillers. The specific surface areas of FNAL fillers reached a maximal value at 516 m2/g, as they were modified using an optimal weight ratio of PEg-MAH to ATNAL at 8. Achievable draw ratio (Dra) values of UHMWPE/NAL (F100Ay), UHMWPE/ATNAL (F100Ax%-8-y) and/or UHMWPE/FNAL (F100Ax%-8FPEzy) as-prepared fibers approached a maximal value as NAL, ATNAL, and/or FNAL contents reached an optimal value at 0.1, 0.1, and 0.075 phr, respectively. The maximal Dra values of F100Ax%-8FPEz0.075 as-prepared fiber specimens were significantly higher than those of F100A0.1 and F100Ax%-8-0.1 as-prepared fiber specimens. In which, the maximal Dra values obtained for F100Ax%-8FPEz0.075 as-prepared fibers reached another maximal value as FNAL fillers were modified using an optimal weight ratio of PEg-MAH to ATNAL at 8. The ultimate tensile strength value of F100A2%-8FPE80.075 drawn fiber reached 6.4 GPa, which was about 2.4 times of that of the UHMWPE drawn fibers prepared at the same optimal UHMWPE concentration and drawing condition. POLYM. ENG. SCI., 55:2205–2214, 2015. © 2015 Society of Plastics Engineers

The miscibility, bioactivity, and antibacterial properties of chitosan/collagen specimens were systematically studied. The specimens were prepared by blending collagen and chitosan with varying deacetylation degrees in solutions; the collagen molecules had been extracted from pigskins using the acid swelling-pepsin digestion method. To understand the miscibility properties of collagen and chitosan molecules, the intrinsic viscosity and differential scanning calorimetry analysis of collagen, chitosan, and collagen/chitosan specimens were performed. The instrinsic viscosity measurements suggested that chitosan and collagen molecules with varying deacetylation degrees were miscible at molecular level for all compositions and degrees of deacetylation of chitosan/collagen mixture solutions prepared in this study. Fourier transform infrared analyses suggested that the percentage of preserved triple helix structures present in collagen molecules in collagen/chitosan specimens decreased with increasing chitosan c...

A series of Sr-substituted lanthanum manganite perovskites, La1-xSrxMnO3 (LSMO, x = 0, 0.1, 0.2, and 0.3), with mesoporous structures were prepared and coated onto a three-dimensional Ni metal foam (MF) as composite catalysts. The catalytic performances of La0.8Sr0.2MnO3/MF and La0.7Sr0.3MnO3/MF were found to be superior to those of La0.9Sr0.1MnO3/MF, LaMnO3/MF, and LaMnO3 powder in terms of catalytic oxidation of carbon monoxide with air. Under the reaction conditions (1.5 vol.% CO and air balance at a weight hourly space velocity of 90,000 hr–1), La0.8Sr0.2MnO3/MF reached 100% catalytic oxidation of CO, which is 27% higher than that of LaMnO3 powder. Sr substitution induced an increase of Mn4+ and adsorbed surface oxygen species (O–, O2–, or O22–), which increased the number of active centers for oxidation and thus enhanced the oxidizing ability of the catalyst. The high activity and excellent stability of La0.8Sr0.2MnO3/MF catalyst can be ascribed to a synergistic effect between the mesoporous structure and the high number of adsorbed oxygen species of the catalyst as well as the interconnected three-dimensional reticular configuration of the nickel metal support, which increases the number of active sites and enhances mass transfer for CO and O2. La0.8Sr0.2MnO3/MF composite can potentially be used in catalytic converters for CO removal of automotive exhaust gases.

Novel ultrahigh molecular weight polyethylene (UHMWPE)/bacterial cellulose (BC) (F100BCy) and UHMWPE/modified bacterial cellulose (MBC) (F100MBCx-y) as-prepared fibers were prepared and ultra-drawn. The achievable draw ratio (Dra) values of each F100MBCx-y as-prepared fiber series specimens approached a maximum value as their MBC contents reached the optimal value at 0.0625phr. In which, the maximum Dra value obtained for F100MBCx-0.0625 as-prepared fiber specimen prepared at the optimal MBC content reached another maximum value at 347 as the weight ratio of maleic anhydride grafted polyethylene to BC approach an optimal value at 10. In contrast, no significant improvement in Dra values was found for F100BCy as-prepared fiber specimens. To understand these interesting ultradrawing properties described above, Fourier transform infra-red, specific surface areas, and transmission electron microcopic analyses of original and modified BC nanofibers together with the thermal, orientation and tensile properties of F100BCy and F100MBCx-y fiber specimens were performed.

In this investigation, effects of argon plasma on surface modification of ultra high molecular weight polyethylene (UHMWPE) textile were studied. After argon plasma treatment, the peeling test of UHMWPE textile/adhesive (PU_T01) composites were measured by ISO 10339:2003 and then observed the morpho-surface composites by SEM analysis. In addition, the contact angle of UHMWPE textile by argon plasma was also measured. Results showed that the peel strength of UHMWPE textile/adhesive (PU_T01) composites was increased from 0.6 kgf/in to 4.6 kgf/in as argon plasma treatment with treated power of 40 W and treated time of 5 min. From SEM observation, the surface of UHMWPE textile was introduced the number of anchors after argon plasma treatment. After plasma treatment, the UHMWPE react with adhesive. And the contact angle on surface of UHMWPE textile was decreased from 80° to 28°.

The thermal, mechanical, and biodegradation properties of composite materials made from polylactide (PLA) and rice straw fibre (RSF) were evaluated. To improve the properties of PLA/RSF composites, glycidyl methacrylate (GMA)-grafted polylactide (PLA-g-GMA) and treated (crosslinked) rice straw fibre (TRSF) were used to prepare the composites. The result showed that PLA-g-GMA/TRSF had noticeably superior mechanical properties compared with PLA/RSF because of greater compatibility between the polymer and TRSF. The dispersion of TRSF in the PLA-g-GMA matrix was more homogeneous, because branched and crosslinked macromolecules formed via condensation of the glycidyl methacrylate groups of PLA-g-GMA and the hydroxyl groups in TRSF. In addition, the PLA-g-GMA/TRSF composites were more easily processed because of their lower melt viscosities. The water resistance of PLA-g-GMA/TRSF was higher than that of PLA/RSF, although the weight loss of composites buried in soil compost indicated that both were biodegradable, especially at high levels of RSF substitution. The PLA/RSF and PLA-g-GMA/TRSF composites were more biodegradable than was pure PLA.

Dimensions of conical dies were found to have a significant influence on thermal, morphological, orientation, ultradrawing, and dynamic mechanical properties of the as-prepared and/or drawn ultrahigh molecular weight polyethylene (UHMWPE) fiber specimens prepared in this study. Many demarcated “micro-fibrils” were found paralleling to fiber direction of the as-prepared UHMWPE fiber specimens. The percentage crystallinity, melting temperatures, orientation factor (fo) and achievable draw ratio (Dra) values of each as-prepared UHMWPE fiber specimen prepared at a fixed length of outlet land reach a maximum value, as the entry angles of the conical die approach the optimum value at 75°. The maximum fo and Dra values obtained for each F2075-y as-prepared fiber series specimens prepared using the optimum entry angle reach another maximum value as their length of outlet land approach the optimum value of 6.5 mm. The ultimate tensile strengths and moduli of the drawn UHMWPE fibers prepared at the optimum entry angle and length of outlet land are significantly higher than those of fibers prepared at other conditions but stretched to the same draw ratio. Possible reasons accounting for the above interesting properties were discussed in this study. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers

The effects of calcium chloride (CaCl2) on polyamide 6 (PA6) electrospun fibers were investigated on this study. The interaction between CaCl2 and PA6 could affect the crystaline of PA6. XRD, DSC and FTIR revealed that the crystaline of PA6 reduced with increasing CaCl2. Moreover, the addition of CaCl2 could modify PA6 spinning solution properties, i.e., conductivity, surface tension and viscosity. The interaction between CaCl2 and PA6 has an important influence on morphological appearance and sizes of the resulting PA6 electrospun fibers.

Ultrahigh molecular weight polyethylene (UHMWPE)/nanosilica (F2Sy) and UHMWPE/modified nanosilica (F2Smx-y) as-prepared fibers were prepared by spinning of F2Sy and F2Smx-y gel solutions, respectively. Modified nanosilica particles were prepared by grafting maleic anhydride grafted polyethylenes onto nanosilica particles. The achievable draw ratios (Dra) of F2Sy and F2Smx-y as-prepared fibers approached a maximal value as the original and modified nanosilica contents reached corresponding optimum values; the maximal Dra value obtained for F2Smx-y as-prepared fiber specimens was significantly higher than that of the F2Sy as-prepared fiber specimens prepared at the optimum nanosilica content. The melting temperature and evaluated lamellar thickness values of F2Sy and F2Smx-y as-prepared fiber series specimens decrease, but crystallinity values increase significantly, as their original and modified nanosilica contents respectively increase. Similar to the achievable drawing properties of the as-prepared fibers, the orientation factor, tensile strength (σf) and initial modulus (E) values of both drawn F2Sy and F2Smx-y fiber series specimens with a fixed draw ratio reach a maximal value as the original and/or modified nanosilica contents approach the optimum values; the σf and E values of the drawn F2Smx-y fiber specimens are significantly higher than those of the corresponding drawn F2Sy fiber specimens prepared at the same draw ratios and nanosilica contents but without being modified. To understand the interesting ultradrawing, thermal, orientation and tensile properties of F2Sy and F2Smx-y fiber specimens, Fourier transform infrared, specific surface area and transmission electron microscopy analyses of the original and modified nanosilica were performed in this study. © 2012 Society of Chemical Industry

The drawing and ultimate tenacity proper- ties of the Polyamide 6 (PA6)/Attapulgite (ATP) compos- ite fiber specimens prepared at varying modified ATP (mATP) contents and drawing condition were systemati- cally investigated. As evidenced by Fourier transform infrared (FTIR) and morphological analysis, demarcated translucent resins were found firmly attached on the surfa- ces of ATP nanofibers. The specific surface areas of the mATP specimens reached a maximum value at 381 m 2 /g as the weight ratios of silane coupling agents to ATP nanofibers reached an optimum value at 1.0. The percent- age crystallinity and melt shear viscosity values measured at varying shear rates of PA6x(mATP)y specimens increased consistently as their mATP contents increased. In contrast, melting temperatures of PA6x(mATP)y speci- mens reduced slightly as their mATP contents increased. At a fixed drawing temperature and rate, the achievable draw ratio (Dra) values of PA6x(mATP)y as-spun fiber specimens approach a maximum value, as their mATP contents are close to the 0.2 wt % optimum value. The maximum Dra values obtained for PA699.8(mATP)0.2 as- spun fiber specimens reached another maximum, when their drawing temperatures and rates approached the opti- mum values at 120 � C and 50 mm/min, respectively. At a fixed draw ratio, the tenacity values of PA6x(mATP)y drawn fiber specimens drawn at the optimum drawing temperature and rate reached a maximum value, as their mATP contents approached the 0.2 wt % optimum value. Possible reasons accounting for the interesting morpholog- ical, specific surface area, drawing, orientation, and ultimate tenacity properties found for the PA6x(mATP)y fiber specimens are proposed. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: 1906-1916, 2012

The biocompatibility, morphology, and mechanical thermal properties of composite materials composed of maleic anhydride-grafted polylactide (PLA-g-MA) and cellulose acetate (CA) were evaluated. Composites containing maleic anhydride-grafted PLA (PLA-g-MA/CA) exhibited noticeably superior mechanical properties due to greater compatibility between the two components. The dispersion of CA in the PLA-g-MA matrix was highly homogeneous as a result of ester formation, and the consequent creation of branched and cross-linked macromolecules, between the carboxyl groups of PLA-g-MA and hydroxyl groups in CA. The human skin dermal fibroblasts (FBs) seeded on these two novel series membranes to verify the wound dressing characterization properties. With time-dependent course, the FBs proliferation demonstrated a better increasing performance on the series membranes of PLA/CA than PLA-g-MA/CA. The immunofluorescent staining illustrated FBs with normal morphological features. The collagen amount from FBs on the PLA/CA series was 25% higher than that seeded on regular culture-plates after 7 days incubation. With CA content from 0 to 20%, the collagen amount increased apparently and up to the position of CA20%. Otherwise, with PLA-g-MA membranes, the collagen amount showed moderate stimulations. The SEM image presented secreted collagen from FBs on the PLA/CA membrane, indicating the bio-functional properties of these membranes. The above result analysis, this PLA-g-MA/CA composites has good mechanical properties and biocompatible, in the future when use adjusts the formula according to the functionality, may increase the product utility. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

This study systematically investigated the drawing and ultimate tenacity properties of the Nylon 6 (NY6)/nylon 6 clay (NYC) composite fiber specimens prepared at varying NYC contents and drawing temperatures. The achievable draw ratio (Dra) values of NY6x(NYC)y as-spun fiber specimens initially increase in conjunction with NYC content, and then approach a maximum value, as their NYC contents and drawing temperature approach the 0.5 wt% and 120°C, respectively. The percentage crystallinity (Xc) values of NY6x(NYC)y as-spun fiber specimens increased significantly, as their NYC contents increased from 0 to 2 wt%. As revealed by high power wide angle X-ray diffraction analysis, α form NY6 crystals grew at the expense of γ form NY6 crystals originally present in NY6x(NYC)y as-spun fiber specimens as their draw ratios increased. The ultimate modulus, tenacity, and orientation factor values of NY6x(NYC)y fiber specimens approach a maximum value, as their NYC contents and drawing temperatures approach the 0.5 wt% and 120°C optimum values, respectively. The thermal and melt shear viscosity experiments were performed on NY6x(NYC)y resins and/or fiber specimens to determine the optimum NYC content and possible deformation mechanisms accounting for the interesting drawing, orientation, and ultimate tenacity properties found above. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

Poly(ethylene glutaric-co-terephthalate) copolyester “FePol” (FP) together with a kind of citrate ester plasticizer named acetyl tributyl citrate (ATBC) were chosen to prepare PLA/FP/ATBC blends for melt blowing. Only at 250°C and 10 wt % ATBC content, those (PLAxFPy)aATBCb specimens are associated with proper rheological properties for processing melt-blown nonwovens. As suggested by SEM, FTIR and DSC analysis, the compatible behavior between PLA and FP molecules was observed as FP content is equal to or less than 5 wt %. Further morphological analysis of (PLAxFPy)90ATBC10 specimens reveal that relatively fluffy and well-formed nonwoven fabrics were found for (PLAxFPy)90ATBC10 nonwoven specimens melt-blown at FP contents equal to or lower than 5 wt %. In fact, addition of FP can effectively improve tensile and burst properties of (PLAxFPy)90ATBC10 nonwovens, wherein their tensile and burst properties approach the maximum values as FP contents reach around 5 wt %. Possible reasons accounting for these melt-blown properties of (PLAxFPy)90ATBC10 specimens are proposed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

An investigation of the influence of the contents of original and modified attapulgite (ATP) on the ultradrawing properties of ultrahigh-molecular-weight polyethylene (UHMWPE)/ATP (FAx) and UHMWPE/modified ATP (FAmx) as-prepared fibers is reported. Similar to what is found for the orientation factor values, the achievable draw ratios (Dra) of the FAx and FAmx as-prepared fibers approach a maximum value as the original ATP and/or modified ATP contents reach their corresponding optimum values. The maximum Dra value obtained for FAmx as-prepared fiber specimens is significantly higher than that for FAx as-prepared fiber specimens prepared at the optimum original ATP content. Similar to what is found for the orientation factors and achievable drawing properties, the tensile strength (σf) and initial modulus (E) of both drawn F2Ax and F2Amx fiber series specimens with a fixed draw ratio reach maximum values as the original and/or modified ATP contents approach the optimum values, respectively. The σf and E values of the F2Amx fiber specimens are always significantly higher than those of the corresponding F2Ax fiber specimens prepared at the same draw ratios and ATP contents but without being modified. To understand the interesting ultradrawing, orientation and tensile properties of FAx and FAmx fiber specimens, Fourier transform infrared spectral, specific surface area, transmission electron microscopic and elemental analyses of the original and modified ATPs were performed. Copyright © 2012 Society of Chemical Industry

The drawing, tenacity and thermal properties of nylon 6 (NY6)/nylon 6 clay (NYC) composite fiber specimens prepared at varying NYC contents and drawing temperatures were investigated. The achievable draw ratio (Dra) values of NY6x(NYC)y as-spun fiber specimens initially increase in conjunction with NYC content, and then approach a maximum value, as their NYC contents and drawing temperature approach the 0.5 wt% and 120 oC, respectively. The percentage crystallinity (Xc) values of NY6x(NYC)y as-spun fiber specimens increased significantly, as their NYC contents increased from 0 to 2 wt%. The thermal property were performed on NY6x(NYC)y resins and/or fiber specimens to determine the optimum NYC content and possible deformation mechanisms accounting for the interesting drawing properties found above.

A mono-azetidine compound had been demonstrating a ring opening reaction with carboxylic acid (e.g., trimethylacetic acid, TMAA) and that resulted in an amino ester bond formation at ambient temperature. A triazetidine compound (trimethylolpropane tris(1-azetidinyl)propionate, TMPTA-AZT) was obtained via Michael addition of azetidine (AZT) to trimethylolpropane triacrylate (TMPTA). The carboxylic groups of anionic aqueous-based polyurethanes (PU) served as internal emulsifier, which stabilized PU dispersion and also served as PU curing sites. The triazetidine compound (TMPTA-AZT) was introduced into anionic aqueous-based PU dispersion as a new latent curing agent and that mixture became a single-component self-curable aqueous PU system. A crosslinked PU film was obtained from this PU system on drying at ambient temperature. The final polymer performance properties demonstrated the crosslinking behaviors of this new curing agent, TMPTA-AZT, with carboxylic ion-containing aqueous-based PU resins. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The attapulgite powders modified by silicane coupling agent are loaded onto the surface of nylon 6 nanofibers by immersing the nylon 6 electrospun fiber nonwoven in a bath containing modified attapulgite dispersion under ultrasonicating. The nylon6 nanofibrous nonwoven containing attapulgite nano particles was explored as “nano adsorbent” to remove Cd (II) ions from Cd (II) aqueous solution. The effects of various parameters on adsorption properties, such as contact time, pH values of Cd (II) solution and initial Cd (II) concentration were investigated.

The influences of the dispersion level of carbon nanotubes (CNTs) and functionalized CNTs on the transmittance properties of ultrahigh-molecular weight polyethylene (UHMWPE) gel solutions and on ultradrawing properties of their as-prepared fibers are reported. The transmittance properties suggest that the dispersion level of functionalized CNTs in UHMWPE/functionalized CNTs gel solution is significantly better than plain CNTs in UHMWPE/CNTs gel solutions. The orientation factors, achievable draw ratios, tensile strength (σf), and modulus (E) values of UHMWPE/CNTs (FxCy) and UHMWPE/functionalized CNTs (FxCf-y) as-prepared fiber specimens reached a maximum value as their CNT and functionalized CNT contents approached optimum contents at 0.00015 and 0.0001 wt%, respectively. The σf and E values of both FxC0.0012 and FxCf-0.001 series fiber specimens prepared at their optimum CNT and functionalized CNT contents reached another maximum as their UHMWPE approached optimum UHMWPE concentration of 1.7 wt%. Possible reasons accounting for these interesting properties are proposed. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

Novel composite sulfonated poly(ether sulfone)(SPES)/phosphotungstic acid (PWA)/attapulgite (AT) membranes were investigated for direct methanol fuel cells (DMFCs). Physical–chemical properties of the composite membranes were characterized by FTIR, DSC, TGA, SEM-EDX, water uptake, tensile test, proton conductivity, and methanol permeability. Compared with a pure SPES membrane, PWA, and AT doping in the membrane led to a higher thermal stability and glass transition temperature (Tg) as revealed by TGA and DSC. Tensile test indicated that lower AT content (3%) in the composite can significantly increase the tensile strength, while higher AT loading demonstrated a smaller contribution on strength. Proper PWA and AT loadings in the composite membranes can increase the proton conductivity and lower the methanol cross-over. The proton conductivity of the SPES-P-A 10% composite membrane reached 60% of the Nafion 112 membrane conductivity at room temperature while the methanol permeability was only one-fourth of that of Nafion 112 membrane. This excellent performances of SPES/PWA/AT composite membranes could indicate a potential feasibility as a promising electrolyte for DMFC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

In this study, the multi-walled carbon nanotube (MWNT)–polypyrrole (PPy) was synthesized by chemical oxidative polymerization using cetyltrimethylammonium bromide (CTAB) as the cationic surfactant. The high electric conductivity of the MWNT–PPy(Cl − ) was affirmed by the measurement of 4-point-probe method. Then, the MWNT–PPy(Cl − ) was used as conductive fillers and was compounded with ethylene–vinyl acetate (EVA) by blending to form polymeric composite (MWNT–PPy(Cl − )/EVA) that possesses excellent electromagnetic interference shielding (EMI SE). Because of the high conductivity of the MWNT–PPy(Cl − ) (29/71 wt.%), the MWNT–PPy(Cl − ) would interdict the conductive network in the composites. This polymeric composite material could shield the electromagnetic wave. As the cationic surfactant CTAB was added in the MWNT–PPy(Cl − ) chemical oxidative polymerization process, the effect of the surfactant was dispersed, absorbed and attenuated on the MWNT in the chemical oxidative polymerization. For this reason, the EMI SE of the MWNT–PPy(Cl − )/EVA composites had an obvious improvement from 10–15 dB to 45–55 dB. In this investigation, the optimum conductive filler was 75.0 phr PPy(Cl − ) coated on 18.0 phr MWNT. The morphology of the composite also presented a uniform conducting network when a lot of MWNT–PPy(Cl − ) was added.

The influence of calcium chloride (CaCl2) contents on the drawing and tensile properties of polyamide 6 (PA6)/CaCl2 composite fibers prepared at varying drawing temperatures were investigated. At any fixed drawing temperature, the achievable draw ratio (Dra) values of PA6x(CaCl2)y as-spun fiber specimens approach a maximum value, as their CaCl2 contents are close to the 3 wt% optimum value. The maximum Dra values obtained for PA6x(CaCl2)y as-spun fiber specimens prepared at the optimum CaCl2 content reach another maximum as their drawing temperatures approach the optimum drawing temperature at 120 °C. The initial modulus, tensile strength and birefringence values of the PA6 and PA6x(CaCl2)y fiber specimens were found to improve consistently with Dra or with drawing temperatures when they were stretched to a fixed Dra. Similar to those found for their achievable drawing properties, the ultimate initial modulus, tensile strength and birefringence values of PA6x(CaCl2)y fiber specimens approach a maximum value, as their CaCl2 contents and drawing temperatures approach the 3 wt% and 120 °C optimum values, respectively. Experiments including thermal, FTIR, melt shear viscosity and wide angle X-ray diffraction experiments were performed on the PA6x(CaCl2)y resin and/or fiber specimens to clarify the possible reasons accounting for the interesting drawing, tensile and birefringence properties found for the PA6x(CaCl2)y fiber specimens.

The drawing properties of the modified PA 6 (MPA) fiber specimens prepared at varying drawing temperature were systematically investigated, wherein the MPA resins were prepared by reactive extrusion of PA 6 with the compatibilizer precursor (CP). At any fixed drawing temperature, the achievable draw ratio (Dra) values of MPA as-spun fiber specimens increase initially with increasing CP contents, and then approach a maximum value, as their CP contents are close to the 5 wt% optimum value. The maximum Dra values obtained for MPA as-spun fiber specimens prepared at the optimum CP content reach another maximum as their drawing temperatures approach the optimum drawing temperature at 120 °C. The tenacity and birefringence values of PA 6 and MPA fiber specimens improve consistently as their draw ratios increase. Similar to those found for their achievable drawing properties, the ultimate tenacity and birefringence values of MPA fiber specimens approach a maximum value, as their CP contents and drawing temperatures approach the 5 wt% and 120 °C optimum values, respectively. Investigations including Fourier transform infrared, melt shear viscosity, gel content, thermal and wide angle X-ray diffraction experiments were performed on the MPA resin and/or fiber specimens to clarify the optimum CP content and possible deformation mechanisms accounting for the interesting drawing and ultimate tensile properties found for the MPA fiber specimens prepared in this study.

The drawing and ultimate tensile properties of the modified PA 6 (MPA) fiber specimens prepared at varying drawing temperature were systematically investigated, wherein the MPA resins were prepared by reactive extrusion of PA 6 with the compatibilizer precursor (CP). At any fixed drawing temperature, the achievable draw ratio (Dra) values of MPA as-spun fiber specimens increase initially with increasing CP contents, and then approach a maximum value, as their CP contents are close to the 5 wt% optimum value. The maximum Dra values obtained for MPA as-spun fiber specimens prepared at the optimum CP content reach another maximum as their drawing temperatures approach the optimum drawing temperature at 120°C. The tensile and birefringence values of PA 6 and MPA fiber specimens improve consistently as their draw ratios increase. Similar to those found for their achievable drawing properties, the ultimate tensile and birefringence values of MPA fiber specimens approach a maximum value, as their CP contents and drawing temperatures approach the 5 wt% and 120°C optimum values, respectively. Investigations including Fourier transform infrared, melt shear viscosity, gel content, thermal and wide angle X-ray diffraction experiments were performed on the MPA resin and/or fiber specimens to clarify the optimum CP content and possible deformation mechanisms accounting for the interesting drawing, birefringence, and ultimate tensile properties found for the MPA fiber specimens prepared in this study. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers