Synthesis and characterization of poly(L‐lactide‐co‐ϵ‐caprolactone)‐b‐poly(L‐lactide) biodegradable diblock copolyesters: Effect of the block lengths on their thermal properties

Poly(L ‐lactide‐co‐ε‐caprolactone)‐b‐poly(L ‐lactide) [P(LL‐co‐CL)‐b‐PLL] diblock copolyesters were synthesized in a two‐step process with 1‐dodecanol (DDC) and stannous octoate as the initiating system. In the first‐step reaction, a 50:50 mol % amorphous poly(L ‐lactide‐co‐ε‐caprolactone) [P(LL‐co‐CL)] copolyester was synthesized via the bulk copolymerization of L ‐lactide and ε‐caprolactone, which was followed by the polymerization of the PLL crystalline block at the end chain in the second‐step reaction. The yielded copolyesters were characterized with dilute‐solution viscometry, gel permeation chromatography, ¹H‐ and ¹³C‐NMR, and differential scanning calorimetry methods. The molecular weights of the P(LL‐co‐CL) copolyesters from the first‐step reaction were controlled by the DDC concentrations, whereas in the second‐step reaction, the molecular weights of the P(LL‐co‐CL)‐b‐PLL diblock copolyesters depended on the starting P(LL‐co‐CL) copolyester molecular weights and L ‐lactide/prepolymer molar ratios. The starting P(LL‐co‐CL) copolyester molecular weights and PLL block lengths seemed to be the main factors affecting specific thermal properties, including the melting temperature (T_m), heat of melting (ΔH_m), crystallizing temperature (T_c), and heat of crystallizing (ΔH_c), of the final P(LL‐co‐CL)‐b‐PLL diblock copolyester products. T_m, ΔH_m, T_c, and ΔH_c increased when the PLL block lengths increased. However, these thermal properties of the diblock copolyesters also decreased when the P(LL‐co‐CL) block lengths increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Crystallization behavior of poly(ethylene terephthalate‐co‐neopentyl terephthalate‐co‐ethylene isophthalate‐co‐neopentyl isophthalate) copolyester and its application in laminated tin‐free steel

A low crystallinity, the copolyester poly(ethylene terephthalate‐co‐neopentyl terephthalate‐co‐ethylene isophthalate‐co‐neopentyl isophthalate) (PENIT) was synthesized and applied for laminated tin‐free steel. The structures and thermal properties of the copolyester were characterized by ¹H‐NMR, thermogravimetry analysis, differential scanning calorimetry, wide‐angle X‐ray diffraction, and polarized optical microscopy. Differential scanning calorimetry, wide‐angle X‐ray diffraction, and polarized optical microscopy results show that the crystallization ability of the copolyester decreased obviously. Meanwhile, the peel strength, crystallinity, and water‐vapor permeability of the copolyester film were also measured at varied lamination temperatures. The result confirm that an improvement in the lamination temperature led to an increased ratio of amorphous PENIT to crystalline PENIT and decreased structural orientation, and the decrease in the structural orientation sped up the increase in the rate of water‐vapor permeability. On the basis of the purpose of reducing a detrimental effect on the corrosion resistance caused by water permeation, a reasonable lamination temperature was selected. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42308.     

Synthesis and characterization of poly(L‐lactic acid)‐b‐poly(ethylene terephthalate‐co‐sebacate)‐b‐poly(L‐lactic acid) copolyesters

Random copolyester namely, poly(ethylene terephthalate‐co‐sebacate) (PETS), with relatively lower molecular weight was first synthesized, and then it was used as a macromonomer to initiate ring‐opening polymerization of l ‐lactide. ¹H NMR quantified composition and structure of triblock copolyesters [poly(l ‐lactic acid)‐b‐poly(ethylene terephthalate‐co‐sebacate)‐b‐poly(l ‐lactic acid)] (PLLA‐PETS‐PLLA). Molecular weights of copolyesters were also estimated from NMR spectra, and confirmed by GPC. Copolyesters exhibited different solubilities according to the actual content of PLLA units in the main chain. Copolymerization effected melting behaviors significantly because of the incorporation of PETS and PLLA blocks. Crystalline morphology showed a special pattern for specimen with certain composition. It was obvious that copolyesters with more content of aromatic units of PET exhibited increased values in both of stress and modulus in tensile test. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Lasting high surface energy co‐polyester ionomer and its application in laminated tin‐free steel

A lasting high surface energy co‐polyester poly[ethylene terephthalate‐co‐ethylene isophthalate sodiosulfonate‐co‐poly(ethylene glycol)] polyester (PEPST) was synthesized and applied in laminated tin‐free steel (TFS). The structures and properties of the co‐polyester were characterized by nuclear magnetic spectra (¹H‐NMR), thermogravimetry, differential scanning calorimetry, polarized optical microscopy, and surface energy tests. Meanwhile, the peel strength and corrosion resistance of the co‐polyester film were also measured. The results confirm that an improvement in the lamination temperature leads to PEPST film peel strength increases, and crystalline and corrosion resistance decrease. Based on the purpose of reducing a detrimental effect on corrosion resistance, a reasonable lamination temperature was determined. Scanning electron microscope and energy dispersive X‐ray analysis prove the interface combination morphology of laminated TFS. Anticorrosion property analysis shows PEPST film has good anticorrosion performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45174.     

Preparation and performance of a transparent poly(3,4‐ethylene dioxythiophene)–poly(p‐styrene sulfonate‐co‐acrylic acid sodium) film with a high stability and water resistance

Poly(p‐styrene sulfonate‐co‐acrylic acid sodium) (PSA) from the copolymerization of acrylic acid sodium and p‐styrene sulfonate monomers were used to dope poly(3,4‐ethylene dioxythiophene) (PEDOT) to generate PEDOT–PSA antistatic dispersions. Compared to those of the PEDOT–poly(p‐styrene sulfonate sodium) (PSS), the physical and electrical properties of the PEDOT–PSA conductive liquids were much better. The PEDOT–PSA films possessed a better water resistance without a decrease in the conductivity. The sheet resistance of the PEDOT–PSA–poly(ethylene terephthalate) (PET) films was about 1.5 × 10⁴ Ω/sq with a 100 nm thickness, the same as the PEDOT–PSS–PET films. The transmittance of the PEDOT–PSA–PET films exceeded 88%. Furthermore, the environmental dispersity of the PEDOT–PSA antistatic dispersion was apparently improved by the dopant PSA so that the stability was extraordinarily promoted. Meanwhile, the water resistances of the PEDOT–PSA–PET and PEDOT–PSA films were also enhanced. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45163.     

Basic characterization of polypropene‐block‐poly(methylene‐1,3‐cyclopentane‐co‐propene) synthesized from propene and 1,5‐hexadiene with modified stopped‐flow method

Block copolymerization of propene and 1,5‐hexadiene was carried out by a modified stopped‐flow polymerization method with an MgCl₂‐supported Ziegler catalyst. The resulting polymer, polypropene‐block‐poly(methylene‐1,3‐cyclopentane‐co‐propene) (PP‐b‐(PMCP‐co‐PP)), in which the crystallizable PP part was linked with the non‐crystallizable PMCP‐co‐PP part, was characterized by optical microscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and tensile testing. The block copolymer having a chemical linkage between PP and PMCP‐co‐PP showed properties different from those of homopolymer, random copolymer and blend polymer. © 2001 Society of Chemical Industry     

Fabrication of speedy and super‐water‐absorbing non‐woven cloth with hierarchical three‐dimensional network structure

A novel speedy and super‐water‐absorbing non‐woven cloth with hierarchical three‐dimensional network (3D‐SS‐PET) was fabricated through the induction of UV copolymerization on polyethylene terephthalate (PET) fibers followed by a volume phase transition. The macroscopic three‐dimensional network implied that the PET non‐woven substrates are complicated three‐dimensional fibrous materials including oriented fibers in preferential or random directions. The microscopic three‐dimensional network is poly(acrylic acid‐co‐acrylamide) (poly(AA‐co‐AM)) crosslinked copolymer layers on the fiber surface. The rapid volume phase transition was achieved by immersing the swelled non‐woven poly(AA‐co‐AM) modified PET (PET‐g‐AA‐co‐AM) in ethanol. The above process was an essential step to prepare the copolymer chain; after that the fiber surface was extended to form abundant capillary channels and plenty of space between fibers. The water contact angle decreased remarkably from 130° to 0°, while the absorbing capacity of the saturated water and the average water‐absorbing rate experienced an increasing trend, rising from 300 to 324.6 g g^?1 in 24 h and 18.6 and 222 g (g min)^?1 in 40 s, respectively. It was concluded that surface hydrophilicity and capillaries of the hydrophilic modified macroscopic fibrous structure enhanced the water‐absorbing rate and the swelling process contributed to the higher water absorption capacity. This speedy and super‐water‐absorbing material exhibits great potentiality in diapers, sanitary napkins, wound dressings, surgical pads, and hygroscopic and sweat‐free underwear in extremely cold areas. © 2018 Society of Chemical Industry     

Synthesis and properties of random copolymers of 2,2‐dimethyltrimethylene carbonate and ethylene carbonate catalyzed by lanthanide tris(2,6‐di‐tert‐butyl‐4‐methylphenolate)

Random copolymers of 2,2‐dimethyltrimethylene carbonate and ethylene carbonate (EC) were synthesized with lanthanide tris(2,6‐di‐tert‐butyl‐4‐methylphenolate)s [Ln(DBMP)₃; Ln = La, Nd, Sm, or Dy] as catalysts, among which La(DBMP)₃ showed the highest activity. Poly(2,2‐dimethyltrimethylene carbonate‐co‐ethylene carbonate)s [poly(DTC‐co‐EC)]s with high molecular weights were prepared at room temperature and characterized with ¹H‐NMR and size exclusion chromatography. The thermal behavior and crystalline properties of the poly(DTC‐co‐EC)s were analyzed with differential scanning calorimetry, thermogravimetric analysis, and X‐ray diffraction. The crystallinity and melting temperatures of the poly(DTC‐co‐EC)s both decreased with increasing EC content in the copolymers. The mechanical properties of these copolymers were also investigated with dynamic mechanical analysis and tensile strength measurements, which revealed that a reduction of the glass‐transition temperature and great enhancement of the tensile properties could be achieved with higher EC contents. These improvements in the thermal and mechanical properties indicate potential applications in biomedical research for novel polycarbonates. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization, and ion exchange voltammetry study on 2‐acrylamido‐2‐methylpropane sulphonic acid and N‐(hydroxymethyl) acrylamide‐based copolymer

A random copolymer of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and N‐hydroxymethyl acrylamide (NHMA) was prepared by solution polymerization using ceric ammonium nitrate as an initiator. A grade of poly(AMPS)‐co‐poly(NHMA) (PAMPS‐co‐PNHMA) random copolymer was synthesized with AMPS and NHMA. The homopolymerization of AMPS and NHMA was also carried out by the same way as that of random copolymer. PAMPS‐co‐PNHMA and homopolymers of AMPS and NHMA were characterized by FTIR, rheology, FT‐NMR, scanning electron microscope, thermal analysis, and X‐ray diffaractometry. Cyclic voltammetry is used to explain the ion exchange properties of PAMPS‐co‐PNHMA and its possible application in the trace analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of electrorheological active ionomers from poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine)

In this study, synthesis, characterization, partial hydrolysis, and salt formation of poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine), (poly(HEMA)‐co‐poly‐(4‐VP)) copolymers were investigated. The copolymers were synthesized by free radical polymerization using K₂S₂O₈ as an initiator. By varying the monomer/initiator ratio, chain lengths of the copolymers were changed. The copolymers were characterized by gel permeation chromatography (GPC), viscosity measurements, ¹H and ¹³C NMR and FTIR spectroscopies, elemental analysis, and end group analysis methods. The copolymers were partially hydrolyzed by p‐toluene sulfonic acid monohydrate (PTSA·H₂O) and washed with LiOH_(aq) solution to prepare electrorheological (ER) active ionomers, poly(Li‐HEMA)‐co‐poly(4‐VP). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3540–3548, 2006     

Static and dynamic mechanical properties of flame‐retardant copolyester/nano‐ZnCO3 Composites

Novel phosphorus‐containing copolyester nanocomposites were synthesized by in situ polymerization with 2‐carboxyethyl(phenylphosphinic) acid (CEPPA) and nano‐ZnCO₃. The flame retardancy and static and dynamic mechanical properties of poly(ethylene terephthalate) (PET)/nano‐ZnCO₃ composites and phosphorus‐containing copolyester/nano‐ZnCO₃ composites were evaluated with limiting oxygen index measurements, vertical burning testing (UL‐94), a universal tensile machine, and a dynamic mechanical analysis thermal analyzer. The phosphorus‐containing copolyester nanocomposites had higher limiting oxygen indices (ca. 32%) and a V0 rating according to the UL‐94 test; this indicated that nano‐ZnCO₃ and CEPPA greatly improved the flame retardancy of PET. The static mechanical test results showed that the breaking strength, modulus, and yield stress of the composites tended to increase with increasing nano‐ZnCO₃ content; when 3 wt % nano‐ZnCO₃ was added to PET and the phosphorus‐containing copolyester, the breaking strength of the composites was higher than that of pure PET. Dynamic mechanical analysis indicated that the dynamic storage modulus and loss modulus of the PET composites increased markedly in comparison with those of pure PET. However, the glass‐transition temperatures associated with the peaks of the storage modulus, mechanical loss factor, and loss modulus significantly decreased with the addition of ZnCO₃ and CEPPA. The morphologies of the composites were also investigated with scanning electron microscopy, which revealed that nano‐ZnCO₃ was dispersed homogeneously in the PET and copolyester matrix without the formation of large aggregates. In addition, the interfacial adhesion of nano‐ZnCO₃ and the matrix was perfect, and this might have significantly affected the mechanical properties of the composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A facile preparation of pH‐temperature dual stimuli‐responsive supramolecular hydrogel and its controllable drug release

A series of pH‐temperature dual stimuli‐responsive random copolymers poly[N,N‐dimethylaminoethyl methacrylate‐co‐poly(poly(ethylene glycol) methyl ether methacrylate][poly(DMAEMA‐co‐MPEGMA)] were synthesized by free radical polymerization. The supramolecular hydrogel was formed by pseudopolyrotaxane, which was prepared with the host‐guest interactions between α‐cyclodextrin (α‐CD) and poly(ethylene glycol) (PEG) side chains. Fourier transform infrared (FT‐IR), nuclear magnetic resonance (¹H NMR), and X‐ray diffraction (XRD) confirmed the structures of the hydrogels. The pH‐temperature dual stimuli responsive properties of the hydrogels were characterized by rheometer. Finally, the controllable drug release behavior of the hydrogel, which was used 5‐fluorouracil (5‐Fu) as the model drug, was investigated at different temperatures and different pH values. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43279.     

Studies on comonomer compositional distribution and its effect on some physical properties of bacterial poly(3‐hydroxybutyric acid‐co‐3‐hydroxypropionic acid)

Comonomer compositional distribution of bacterially synthesized poly(3‐hydroxybutyric acid‐co‐3‐hydroxypropionic acid) [P(3HB‐co‐3HP)] was investigated via solvent/non‐solvent fractionation techniques. The result indicates the presence of extremely broad comonomer compositional distribution in the original bacterial product. Furthermore, utilizing compositionally fractionated bacterial copolyesters with much narrower comonomer compositional distributions, the 3HP comonomer content‐dependence of their thermal and crystallization behavior was studied by means of differential scanning calorimeter (DSC) and polarized optical microscopy and the results compared with those of unfractionated copolyesters. It was revealed that the physical features of the fractionated copolyester P(3HB‐co‐3HP)s strongly depends on the 3HP comonomer content. In addition, to clarify the effect of the compositional distribution on the properties of the unfractionated copolyester, the miscibility between bacterial poly(3‐hydroxybutyric acid) [P(3HB)] and two fractionated P(3HB‐co‐3HP) samples with 11.3 and 14.9% 3HP was investigated for blends obtained by solvent casting techniques. The evidence of thermal analysis and spherulitic growth rates imply miscibility of the P(3HB)/3HB‐rich P(3HB‐co‐3HP) binary blends. © 1999 Society of Chemical Industry     

Synthesis of ethylene terephthalate and ethylene naphthalate (PET‐PEN) block‐co‐polyesters with defined surface qualities by tailoring segment composition

Ethylene terephthalate and ethylene naphthalate oligomers of defined degree of polymerization were synthesized via chemical recycling of the parent polymers. The oligomers were used as defined building blocks for the preparation of novel block‐co‐polyesters having tailored sequence compositions. The sequence lengths were systematically varied using Design of Experiments. The dispersive surface energy and the specific desorption energy of the co‐polymers were determined by inverse gas chromatography. The study shows that polyethylene terephthalate‐polyethylene naphthalate (PET‐PEN) block‐co‐polyesters of defined sequence lengths can be prepared. Furthermore, the specific and dispersive surface energies of the obtained block‐co‐polyesters showed a linear dependence on the oligomer molecular weight and it was possible to regulate and control their interfacial properties. In contrast, with the corresponding random‐block‐co‐polyesters no such dependence was found. The synthesized block‐co‐polyesters could be used as polymeric modifying agents for stabilizing PET‐PEN polymer blends. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40731.     

Ambient‐cured polyesteramide‐based anticorrosive coatings from linseed oil—A sustainable resource

Ambient‐cured polyesteramide (APEA) coating resin synthesized from dihydroxy fatty amide obtained from linseed oil, a sustainable resource, and poly(styrene‐co‐maleic anhydride), a bifunctional acid component, was found to exhibit improved physicomechanical and anticorrosive properties. The structural elucidation of APEA resin has been carried out by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopies. The physicomechanical and chemical resistance properties were investigated by standard methods. The corrosion resistance performance was evaluated in acid, alkali, and organic solvent. The thermal behavior was studied by TGA technique. A comparative study of these properties of APEA with reported baked polyesteramide (PEA) coatings was carried out. A remarkable improvement in the drying property of APEA was observed. The APEA coatings also showed improved physicomechanical and anticorrosive properties as compared to the baked PEA coatings. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1818–1824, 2005     

Microstructure and crystallization of melt‐mixed poly(ethylene terephthalate)/poly(ethylene isophthalate) blends

Physical blends of poly(ethylene terephthalate) (PET) and poly(ethylene isophthalate) (PEI), abbreviated PET/PEI (80/20) blends, and of PET and a random poly(ethylene terephthalate‐co‐isophthalate) copolymer containing 40% ethylene isophthalate (PET₆₀I₄₀), abbreviated PET/PET₆₀I₄₀ (50/50) blends, were melt‐mixed at 270°C for different reactive blending times to give a series of copolymers containing 20 mol % of ethylene isophthalic units with different degrees of randomness. ¹³C‐NMR spectroscopy precisely determined the microstructure of the blends. The thermal and mechanical properties of the blends were evaluated by DSC and tensile assays, and the obtained results were compared with those obtained for PET and a statistically random PETI copolymer with the same composition. The microstructure of the blends gradually changed from a physical blend into a block copolymer, and finally into a random copolymer with the advance of transreaction time. The melting temperature and enthalpy of the blends decreased with the progress of melt‐mixing. Isothermal crystallization studies carried out on molten samples revealed the same trend for the crystallization rate. The effect of reaction time on crystallizability was more pronounced in the case of the PET/PET₆₀I₄₀ (50/50) blends. The Young's modulus of the melt‐mixed blends was comparable to that of PET, whereas the maximum tensile stress decreased with respect to that of PET. All blend samples showed a noticeable brittleness. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3076–3086, 2003     

Preparation and properties of poly(ether‐ester‐amide)/poly(acrylonitrile‐co‐butadiene‐co‐styrene) antistatic blends

A novel antistatic agent poly(ether‐ester‐amide) (PEEA) based on caprolactam, polyethylene glycol, and 6‐aminocaproic acid was successfully synthesized by melting polycondensation. The structure, thermal properties, and antistatic ability of the copolymer were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analyses, and ZC36 megohmmeter. Test results show that PEEA is a block copolymer with a melting point of 217°C and a thermal decomposition temperature of 409°C, together with a surface resistivity of 10⁸ Ω/sq. Antistatic poly(acrylonitrile‐co‐butadiene‐co‐styrene) (ABS) materials were prepared by blending different content of PEEA to ABS resin. The antistatic performances, morphology, and mechanical properties were investigated. It is indicated that the surface resistivity of PEEA/ABS blends decrease with the increasing PEEA content, and the excellent antistatic performance is obtained when the antistatic agent is up to 10–15%. The antistatic performance is hardly influenced by water‐washing and relative humidity, and a permanent antistatic performance is available. The antistatic mechanism is investigated. The compatibility of the blends was studied by scanning electron microscopy images. The ladder distribution of antistatic agent is formed, and a rich phase of antistatic agent can be found in the surface layer. The elongations at break of the blend are improved with the increasing antistatic agent; the tensile strength and the notched impact strength kept almost the same. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Investigation on the morphological and mechanical properties of (polyamide 6)/(poly[styrene‐co‐acrylonitrile])/(poly[styrene‐b‐{ethylene‐co‐butylene}‐b‐styrene]) ternary blends

In this work, ternary polymer blends based on (polyamide 6)/(poly[styrene‐co‐acrylonitrile])/(poly[styrene‐b‐{ethylene‐co‐butylene}‐b‐styrene]) (SEBS) triblock copolymer and a varying concentration of the reactive (maleic anhydride)‐grafted SEBS were prepared by using a melt‐blending process. The effects of the material parameters (composition of ternary blends and SEBS/[{maleic anhydride}‐grafted SEBS] concentration ratio) and blending sequence on the morphological and mechanical properties of ternary blends were studied. Taguchi experimental design methodology was employed to design the experiments and select the material and processing parameters for the optimized mechanical properties. Tensile properties (Young's modulus and yield stress) and impact strength were considered as the response variables. It was demonstrated that there is a meaningful relationship between the composition of blends, processing parameters, observed phase structure, and obtained mechanical properties. The mechanical tests showed that the highest impact strength was achieved as the dispersion of the rubbery phase achieved an optimum size of about 1 μm. J. VINYL ADDIT. TECHNOL., 23:329–337, 2017. © 2015 Society of Plastics Engineers     

Regulation of the mechanical properties and heat resistance of the poly(l‐lactide‐co‐trimethylene carbonate) copolymer by the incorporation of a stereocomplex crystal and graphene oxide

Stereocomplex crystals of polylactide and graphene oxide (GO) were simultaneously used to regulate the mechanical properties and heat resistance of a poly(l ‐lactide‐co‐trimethylene carbonate) [P(LLA‐co‐TMC)] copolymer. The crystallization behaviors in the nonisothermal cold‐crystallization process of P(LLA‐co‐TMC)–poly(d ‐lactide) (PDLA) blends and P(LLA‐co‐TMC)–PDLA–GO composites were investigated by differential scanning calorimetry, wide‐angle X‐ray diffraction, and polarized optical microscopy. Data from the crystallization kinetics and the crystallization active energy indicated that GO both promoted nucleation and limited growth during the stereocomplex crystallization process. Three kind of samples (without crystallization, with low crystallinity, and with high crystallinity) were used to investigate the mechanical properties and heat resistance. We found a decrease in the elongation at break when the stereocomplex crystal and GO contents were increased, and this was accompanied by an improvement in the tensile strength. The change in the storage modulus value determined by dynamic mechanical analysis demonstrated that both the stereocomplex crystal and GO effectively improved the heat resistance. These results indicate that this study provided a new strategy for fabricating a P(LLA‐co‐TMC) copolymer with good comprehensive properties at was entirely different from common chemical crosslinking methods. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45248.     

Characterization of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) biosynthesized by mixed microbial consortia fed fermented dairy manure

The bioplastic poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), was isolated from a bioreactor using mixed microbial consortia fed volatile fatty acids (VFA), from fermented dairy manure, as the carbon source. The molar fraction of 3‐hydroxyvalerate (3HV) amounted to 0.33 mol mol^?1 for two isolated PHBV samples as determined by GC‐MS and ¹H‐NMR spectroscopy. The chemical, thermal, and mechanical properties were determined. The PHBVs had relatively high M_w (～790,000 g mol^?1). Only a single glass transition temperature (T_g) and melting point (T_m) were observed. Isolated PHBVs exhibited good flexibility and elongation to break as compared with commercial PHBVs with lower HV. The diad and triad sequence distributions of the monomeric units were determined by ¹³C‐NMR spectroscopy and followed Bernoullian statistics suggesting that the PHBVs were random. The PHBV sequence distribution was also characterized by electrospray ionization‐mass spectrometry (ESI‐MSⁿ) after partial alkaline hydrolysis to oligomers showing a random 3HV distribution. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40333.