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[Display omitted] • In-situ polymerization of graphene-based polyamide 66 nanocomposites. • Strong enhancement in mechanical properties and thermal properties. • Synergistic effect of chemical and physical interfacial interactions. In this work, two types of graphene-based polyamide 66 (PA66) nanocomposites were prepared by in-situ polymerization. The effect of the surface functional groups of graphene oxide (GO) and the chemically modified GO (GO-DDA) on the structure and the properties of the nanocomposites were investigated. The nanocomposites achieved excellent enhancement in the properties. Compared to PA66/GO nanocomposites, PA66/GO-DDA nanocomposite showed higher Young's modulus, tensile strength and thermal decomposition temperature at all the filler content. For example, at the filler content of 0.3 wt%, PA66/GO-DDA nanocomposite exhibited 92 % increase in the Young's modulus, while PA66/GO nanocomposite exhibited 42 % increase. The thermal decomposition temperature was improved from 357 °C to 388 °C and to 383 °C by the incorporation of only 0.5 wt% of GO-DDA and GO, respectively. These results indicate the synergy reinforcement effect brought by the chemical interactions and the physical interactions between PA66 and GO-DDA. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-based copolyesters involving 2,6-pyridine structure with isosorbide as a second diol were synthesized. • Incorporation of isosorbide enhanced thermal properties of the pyridine-based polyesters. • Isosorbide significantly improved the mechanical properties of the pyridine-based polyesters. • The copolyesters showed high gas barrier properties. Driven by sustainable development and low-carbon policies, many high-performance bio-based polyesters are produced. Our previous work uncovered the high barrier but low thermal and mechanical properties of a renewable 2,6-pyridinedicarboxylic-based polyester. In this article, the copolymerization with isosorbide as a second diol is considered to ameliorate these properties. The chemical structures of copolyesters and the successful introduction of isosorbide were confirmed by FT-IR and 1H NMR. The 1H NMR spectra also allowed the calculation of isosorbide ratio in polymers. GPC revealed a decrease in molar masses with the increase of isosorbide ratio. Contact angle and water/gas permeation measurements disclosed an increase in hydrophilicity and water/gas permeability with the introduction of isosorbide. TGA and DSC analyses demonstrated an enhancement in thermal stability: 8 mol% of isosorbide to the total diol ratio increased the 5 % weight loss temperature (T 5%) by 9 °C, the maximum weight loss temperature (T max) by 8 °C and the glass transition temperature (T g) by 6 °C. DSC investigation showed that the incorporation of isosorbide significantly influenced the crystallization properties, particularly from the melt, by decreasing the crystallinity. XRD patterns indicated the presence of similar crystallization units in these polyesters. Tensile test revealed that incorporating 8 mol% of isosorbide greatly improved the mechanical properties by doubling Young's modulus and tripling the strength at break. Such enhancement in thermal and mechanical properties is important for high gas barrier food packaging applications of these polyesters. [ABSTRACT FROM AUTHOR]

Two high heat resistance resins, low dielectric constant and low dielectric loss biobased benzoxazine reins were prepared and the nature behind these attractive performances was intensively investigated. [Display omitted] High heat resistance, low dielectric constant and low dielectric loss benzoxazine resin is of great significance to the practical application of information industry. In this article, two biobased benzoxazine monomers HA-dea and H-dea were prepared by mannich reaction using p-hydroxybenzyl alcohol and hordenine as phenol sources and 1,10-diaminodecane as amine sources. The two benzoxazine monomers showed different thermodynamic behaviors. The melting point of HA-dea was 77.5 °C, while H-dea was liquid at room temperature, the viscosity of H-dea at room temperature (25 °C) was 5.517 Pa/s. The curing peak temperatures of the two monomers were 217 and 193 °C, respectively. Both monomers showed excellent processability. Two benzoxazine resins poly(HA-dea) and poly(H-dea) were prepared through thermal curing procedure, and the comprehensive properties of two benzoxazine resins were investigated. The glass transition temperatures (T g) of poly(HA-dea) and poly(H-dea) were 267 °C and 233 °C, respectively, showing excellent heat resistance of the newly prepared resin. Moreover, poly(HA-dea) and poly(H-dea) have both high storage modulus (3341 MPa and 3124 MPa, respectively, measured at 25 °C) and good flexural strength (109 ± 3.6 MPa and 101 ± 3.8 MPa). Moreover, the resins poly(HA-dea) and poly(H-dea) also have low dielectric constant and dielectric loss at 1 MHz, the dielectric constants are 2.78 and 2.56, respectively, and dielectric losses are 0.018 and 0.016, respectively. Among the two resins, poly(HA-dea) exhibits more excellent heat resistance, which may be based on the multi-crosslinking sites and hydrogen bond crosslinking networks. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Interest for biodegradable polymers is increasing driven by sustainability trend. • Use of CNC as reinforcement in polymer nanocomposites is highlighted. • Effect of CNCs on the overall properties of the nanocomposites is discussed. • Focus on rheological, thermal, mechanical, barrier and biodegradation properties. Abstract Cellulose nanocrystals (CNCs) are considered as one of the most attractive renewable reinforcements for biodegradable polymers due to their promising properties and broad range of applications in several fields. However, the knowledge of CNCs effect on the overall properties of these CNC-based nanocomposites is not fully clarified. This review proposes a comprehensive understanding on the effect of CNCs on the rheological, thermal, mechanical, barrier and biodegradation properties of the main biodegradable polymers. This further understanding is expected to facilitate progress in various sectors of nanotechnology and materials science. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) was synthesized from expanded graphite with particle size of 130 μm (GO130) and 1200 μm (GO1200) and characterized. GO130 was oxidized to a higher degree and contained larger concentration of C O bonds. After the synthesis, the GO was kept in a form of viscous slurry in methanol to prevent formation of graphite oxide. The slurry was mixed with a hardener and methanol was evaporated. The nanocomposites with GO content from 0.25 to 1.0 wt% were prepared by mixing the epoxy resin, hardener and hardener/GO mixture and cured. The particles were homogeneously distributed within the polymer matrix as observed by SEM on the plasma etched samples. The glass transition temperature increased from 81 °C to up to 90 °C. The Young’s modulus increased by 35% and 30% with the addition of GO130 and GO1200, respectively, while the tensile strength increased for 10% only when GO1200 had been added. The optimum concentration of GO in the nanocomposite is from 0.25 to 0.50 wt%. [ABSTRACT FROM AUTHOR]

Wood polymer nanocomposites (WPNC) having attractive mechanical and water resistance properties were prepared through a completely green route using a mixture of wheat gluten protein and starch. Starch was blended with wheat gluten protein at different ratios (70/30 and 50/50) and then grafted with methylmethacrylate (MMA). The effect of wheat gluten protein on various properties of the wood composites was investigated. Citric acid was employed to cross-link the wood flour with methylmethacrylate grafted starch-gluten (MMA- g -SG). The most advantageous part of the reaction was the use of water as the reaction media in the entire process to prepare the green composites. To improve the further properties of the composites, different percentage of N-cetyl-N, N, N-trimethyl ammonium bromide (CTAB) modified TiO 2 nanoparticles were incorporated in the composite system and their effects were studied. The interaction among MMA- g -SG, cross-linker, soft wood flour and nanofiller were investigated by FTIR study. The probable interactions among MMA- g -SG, soft wood, modified TiO 2 and citric acid in the formation of wood starch gluten nanocomposites (WSGNC) were established. The density functional theory (DFT) calculations were also used to study the interactions of the nanocomposite. The morphology of the wood starch gluten nanocomposites (WSGNC) was examined by SEM and TEM study. Composite prepared from 50/50 ratio of starch and gluten along with 3 phr TiO 2 exhibited excellent thermal resistance, water resistance and mechanical properties. [ABSTRACT FROM AUTHOR]

This work assesses the potential of maleinized cottonseed oil – MCSO as plasticizer in poly(lactic acid) – PLA films with improved ductile behaviour. The effects of MCSO are compared with commercially available maleinized oil, i.e. maleinized linseed oil – MLO in terms of mechanical, thermal and barrier properties, as well as morphology changes. Plasticized PLA formulations were obtained with a maleinized oil content in the 0–10 wt% range. Addition of both maleinized vegetable oils leads to a slight decrease in the glass transition temperature (T g ) of neat PLA from 63 °C to 60–61 °C. Nevertheless, MCSO provides better overall properties. Addition of 7.5 wt% MCSO increases the elongation at break by 292%. Regarding the barrier properties, both maleinized vegetable oils increase the oxygen transmission rate – OTR. Nevertheless, this increase is less pronounced in the case of MCSO thus indicating its higher efficiency compared to MLO. On the other hand, addition of both maleinized vegetable oils do not compromise the overall disintegration of the obtained PLA formulations, thus positioning these additives as environmentally friendly solutions to increase ductile properties in PLA-based films. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) composites reinforced with two types of graphite nanoplatelets varying in lateral size - small (GNP-S) and large (GNP-L) - were produced via melt compounding. Morphological, thermal, mechanical, and electrical properties were investigated to reveal the influence of particle size. Electron microscopy and X-ray diffraction showed well dispersed small GNP-S particles up to 10 wt.% loading, while large GNP-L particles started to agglomerate at loadings ⩾7 wt.%. Addition of GNPs improved the Young’s modulus of the composites by 10% and 24% for small and large nanoplatelets, respectively, the latter being among the highest reported for PLA/GNP systems. For GNP-L this larger increase could be partly explained by an increase in crystallinity while no such effect was observed for GNP-S. Conversely, GNP-L systems showed embrittlement while polymer yield was preserved for GNP-S. GNP-L resulted in a lower electrical percolation threshold. However, systems based on smaller GNP-S particles showed significantly enhanced conductivity and a reduction in percolation threshold after annealing. Heat distortion temperature (HDT) increased by up to 13 °C, with large GNP-L showing the slightly larger increase. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel magnolol-based epoxy monomer and two furfuryl amines with various side groups were synthesized. • The furfuryl amine containing benzene has a faster curing rate. • The fully bio-based epoxy resin has a high Tg of 168 °C. • The fully bio-based epoxy resins exhibit excellent mechanical and thermal properties. With rapidly shrinking petroleum resources and the deteriorating environment, the use of renewable green bio-based resources to replace petroleum-based raw materials and the development of new bio-based epoxy resins are hot topics of research today. In this study, a new bio-functional epoxy monomer based on magnolol (EMDBP) and two different curing agents based on furfuryl amine with various side groups (PDFA and BDFA) were synthesized and utilized to produce two sets of fully bio-based epoxy thermosets. The non-isothermal and isothermal curing kinetics of EMDBP/PDFA and EMDBP/BDFA were systematically investigated using different scanning calorimetry (DSC) according to the Friedman isoconversional differential method and model-fitting approach, respectively. The results indicate that the autocatalytic curing mechanism dominated the curing reaction of the fully bio-based curing system at a low conversion stage whereas diffusion controlled the curing reaction at a high conversion stage. With an attached benzene ring, BDFA has a more reactive amine group than PDFA. Thus, the curing reaction rate of the BDFA curing system was much faster than that of the PDFA curing system, which also increased significantly with temperature. Additionally, the glass transition temperature of the EMDBP systems (T g , 151.3 °C and 168.4 °C) was increased by 71.3% to 95.7% compared to the diglycidyl ether of bisphenol A (E51) systems (T g , 77.3 °C and 98.3 °C), which was also higher than those of most previously reported fully bio-based epoxy resins. Analysis by nanoindentation and tensile testing showed that the Young's modulus, hardness, tensile strength, and modulus of EMDBP systems were also greatly improved. Furthermore, thermogravimetric investigations demonstrated that EMDBP systems possessed excellent thermal stability at high temperatures, with a char yield of about 47.5 wt% at 800 °C. Consequently, these novel fully bio-based epoxy thermosets with superior heat resistance, mechanical properties, and thermal stability have the potential to replace commercial epoxy resins and be utilized under high temperature environments. [ABSTRACT FROM AUTHOR]

Antibacterial micro- and nanofibrous materials based on polylactide (PLA) and polyethylene glycol (PEG) were prepared by electrospinning. PEG incorporation was achieved by its physical blending with or chemical grafting on PLA. The role of the incorporation method on the surface wettability, the thermal, the mechanical and the biological properties was studied in relation to mats applicability. Physical blending or chemical grafting did not significantly modify the wettability of the mats, but showed a plasticizing effect on PLA – more obvious in the case of the physical blend fibers in agreement with the higher PEG mobility. The mechanical properties of the mats were also influenced by the PEG incorporation method. Fibrous mats of physically blended PLA and PEG proved quasi-ductile, while brittle behavior was registered for the chemically grafted poly( l -lactide)- graft- polyethylene glycol methyl ether acrylate mats. 5-nitro-8-hydroxyquinoline (5N8Q) was loaded as a model antibacterial drug. The polyether incorporation method proved influencing the 5N8Q release profile with burst effect recorded for all PEG-containing mats. Additionally, all drug-loaded mats presented antibacterial activity against Staphylococcus aureus and Escherichia coli . Thus, the choice of polyether incorporation method is dependent on the targeted application of the antibacterial materials. [ABSTRACT FROM AUTHOR]

A high performance, thermoplastic polyurethane elastomer was synthesized with methylene bis(4-cyclohexylisocyanate), 1,4-butanediol as a chain extender and a polycarbonate polyol containing 1,6-hexanediol and 3-methyl-1,5-pentanediol. SAXS data evidences an interdomain “center-to-center” distance of 45 Å. DSC traces evidence one glass transition temperature and weak melting region. Surprisingly, the material is ultra-soft with a Shore A hardness of 64, but does not undergo any blocking. DMA analysis reveals a low temperature secondary relaxation and the glass to rubber transition followed by a rubbery plateau. In tensile set experiments strain recovery averaged 96–98%. The PCPU exhibits partial self-healing after rupture without the addition of additives or imbedded healing agents. Self-healing is attributed to interdiffusion and hydrogen bonding mechanism, where rehealing is possible. FTIR measurements characterize hydrogen bonding. [ABSTRACT FROM AUTHOR]

Ice-templated waxy maize starch. [Display omitted] • Neat anisotropic waxy maize starch cryogels were made via ice-templating method. • The morphology varied from lamellar to sponge-like, controlled by starch concentration. • Cryogels possess anisotropic mechanical and thermal conductivity properties. • Cryogel compression in the transverse direction leads to thermal conductivity decrease. Biodegradable anisotropic neat porous starch materials without any additional cross-linking, plasticizer or any extra matter have been fabricated via facile ice-templating method. Waxy maize was dissolved in water followed by unidirectional freezing and ice sublimation. The influence of process parameters (starch concentration and retrogradation time) on the morphology, density, mechanical properties under the uniaxial compression and thermal conductivity were investigated. The internal morphology and the shape of the pores, from lamellar to sponge-like, was shown to be governed by starch concentration. All porous starches have very low density (0.07–0.15 g/cm3), anisotropic mechanical properties and low thermal conductivity, in particular in transverse direction (0.037–0.048 W/(m·K)). Interestingly, when compressing the ice-templated starches in the transverse direction, the thermal conductivity was further decreased reaching the values of 0.033 W/(m·K). This work provides the guidelines for making fully biobased porous starch materials with controlled morphology and properties. [ABSTRACT FROM AUTHOR]

The thermo-mechanical properties, microstructure, and biocompatibility of a molecular weight series of poly-β-hydroxybutyrate (PHB) produced by Azotobacter vinelandii wild-type strain (OP) and mutant derivatives strains OPN, SOP1 and OPNA were determined. A broad molecular weight range was investigated, spanning from 160 kDa to 2030 kDa. Thermal properties were determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results showed that the melting, crystallization and degradation temperatures of the PHBs initially increased with increasing the molecular weight. However, the highest molecular weight PHBs exhibited cold crystallization and reduction in melting temperature and melting enthalpy, suggesting difficulty to crystallize. Polarized optical microscopy (POM) showed a spherulitic morphology for all PHBs, with a ringed internal structure. Uniaxial tensile tests showed that the mechanical Young’s modulus is an increasing function of molecular weight, whereas the strain at fracture decreased, denoting brittleness as molecular weight increased. Interestingly, the physical properties of these bacterial PHBs were independent of the strain and aeration conditions used in its production. Finally, the PHBs obtained by this novel route did not exhibit any cytotoxic effect and allowed the growth of Human Embryonic Kidney 293 cells (HEK293) on as-cast films indicating the biocompatibility as a support for cell systems. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (GNPs), in different contents, are added to epoxy resin. This work mainly consists of a deep characterization of the composites in order to evaluate their behavior regarding neat epoxy resin. In fact, their main properties, such as their morphological features, their thermo-mechanical and mechanical properties, their electrical conductivity and thermal diffusivity, their hydrophobic behavior and their barrier properties have been studied. It is confirmed that the GNP addition induces an important stiffing of thermosetting resin. However, the rest of mechanical properties, strength and elongation, are diminished due to a weak interface formed between the epoxy matrix and non-functionalized GNPs. The electrical conductivity and thermal diffusivity show an important increase. Electrical conductivity increases several orders of magnitude from a minimum value of percolation while the thermal diffusivity increases proportionally to GNP content. Other advantage of the GNP addition is the increase of the hydrophobic behavior of the composites, determined by measurements of contact angle of water drops. Finally, GNP/epoxy composites present higher barrier properties in humid environments. The addition of GNP decreases the maximum water content absorbed and the diffusion coefficient. However, this enhancement is not too large due to the weak interface and therefore the presence of hollows in the GNP/epoxy composites. [ABSTRACT FROM AUTHOR]

Highlights: [•] Modified PHBV electrospun fibers by the co-solution blending with PEO and its consequent selective removal. [•] The complete PEO removal after soaking in H2O for 7days with daily refreshment. [•] A decrease of the average diameter size (50–75%) after PEO removal. [•] A corrugated and rough surface topography, with nodules, pits, nanopores, shallow and elongated nanoindents. [•] A remarkable reduction (>75%) of the tensile modulus of electrospun PHBV mats. [Copyright &y& Elsevier]

Highlights: [•] Flat thermoplastic polyurethane/carbon nanotubes films were investigated. [•] Morphology/filler/tensile deformation relationships were highlighted. [•] Crystalline aggregates showed features not affected by filler and tensile strain. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-based PLA/PCL melt spun fibers were prepared from electron induced reactive processing (EIReP) toughened PLA/PCL blends. • Significantly enhanced melt strength and elasticity was achieved for the EIReP modified blends. • EIReP modification improved the fiber surface and finally uniform as-spun fibers were achieved. • The EIReP modified fibers with 5 wt% PCL showed 48.7 % increase of fracture strain in comparison with that of its non-irradiated fibers. The effect of electron induced reactive processing (EIReP) on the properties of biodegradable polylactide/masticated polycaprolactone (PLA/PCL) blends was firstly investigated without introducing any chemical additives. Subsequently, the melt spinnability of EIReP modified PLA/PCL blends was explored by a piston spinning. Different PCL concentrations (0, 5 and 10 wt%), applied dose (0, 12.5 and 25 kGy) and take up speeds (500 and 2000 m min−1) were evaluated in order to investigate their influences on the fiber morphology, thermal and mechanical properties. SEM investigation indicated that the non-irradiated PLA/PCL fibers demonstrated less uniform diameter. However, the EIReP modification leads to a homogenous fiber diameter distribution hence uniform as-spun fibers can be produced. The crystallinity of PLA phase increased concomitantly with increased PCL contents for all fibers, whereas it slightly reduced by increasing dose. In addition, the crystallinity degree of neat PLA raised from 6.19 to 36.05% by increasing take up speed from 500 to 2000 m min−1. Interestingly, the irradiated PLA/PCL blend fibers with 5 and 10 wt% PCL demonstrated an increased fracture strain of 48.7 and 34.4%, respectively, compared with their non-irradiated fibers. It can be due to the enhanced chain entanglements and interfacial bonding between two phases. However, the irradiated fibers demonstrated similar initial modulus and reduced tenacity compared with the non-irradiated fibers. [ABSTRACT FROM AUTHOR]

Abstract: Three kinds of benzocyclobutene (BCB)-terminated imide monomers have been synthesized by the imidization and Heck reaction. The obtained BCB monomers exhibit good solubility in a wide range of organic solvents at room temperature. The BCB monomers show an exothermal curing behavior in the range of 220–270°C. The curing kinetic parameters, the apparent activation energy (Ea ), the frequency factor (A) and the reaction order (n), are obtained by non-isothermal DSC method. The cured BCB resins exhibit good thermal stability (Td 5 >435°C), high glass transition temperature (Tg >300°C) and low dielectric constant. Moreover, high quality negative patterns of the BCB films are obtained after the photolithography. [Copyright &y& Elsevier]

Highlights: [•] PU show high E and σt with increasing cohesion energy density. [•] PU networks show higher σt with decreasing Mc . [•] H-bonding is higher in PU with increased urethane group concentration. [•] Formation of cross-links interferes H-bonding. [•] With increasing Mc thermal decomposition of PU began at lower temperature. [ABSTRACT FROM AUTHOR]

Abstract: A series of benzocyclobutene-functionalized siloxane thermosets were prepared to investigate the relationship between the monomer’s chemical structure and the properties of the corresponding polymer. Monomer 1,1,3,3-tetramethyl-1,3-bis[2′-(4′-benzocyclobutenyl)]vinyldisiloxane (DVS-BCB) and 1,3,5,7-tetramethyl-1,3,5,7-tetra[2′-(4′-benzocyclobutenyl)]vinylcyclotetrasiloxane (CYC-BCB) were synthesized by Heck reaction. Copolymer Poly(DVS-BCB-co-POSS) was obtained through incorporating octavinyl-T8-silsesquioxane (Vinyl-POSS) into DVS-BCB matrix via Diels–Alder reaction. The oligomers, P-DVS-BCB, P-CYC-BCB and P-Poly(DVS-BCB-co-POSS), were obtained by refluxing the mesitylene solution of the BCB monomers at the BCB ring opening temperature. The BCB monomers and oligomers showed a similar curing behavior with an exothermic peak temperature near 260°C. The curing kinetic parameters, the apparent activation energy (E a), the frequency factor (A) and the reaction order (n), were obtained by non-isothermal DSC method. The BCB polymers possessed good thermal stability (T d > 450°C in N2). Due to the highly crosslinked network structure, CYC-BCB polymer exhibited higher glass transition temperature, higher modulus and lower coefficient of thermal expansion than DVS-BCB and Poly(DVS-BCB-co-POSS) polymers. Moreover, the BCB polymers also demonstrated low dielectric constants (<2.8 at 1MHz) and low water absorptions. The films prepared from the BCB oligomer solution showed a well planarization (root-mean-square roughness <0.5nm). [Copyright &y& Elsevier]

Abstract: Wholly aromatic polyisophthalamides (PIPAs) containing free hydroxylic groups were prepared from 5-hydroxyisophthalic acid and sulfonyldianiline by the condensation phosphorylation method, using triphenylphosphite as a condensing agent, in the presence of pyridine. Linear polymers were attained in high yield and high molecular weight, and the properties of the polymers were investigated in comparison with homologous polyisophthalamides without . The presence of did not much modified the solubility of hydroxyl-containing polyisophthalamides as they behaved against common solvents in a similar manner as that of reference polyisophthalamides. However, hydroxyl side groups greatly enhanced the water affinity of polyisophthalamides, which showed up to 16% water uptake in 98% relative humidity, and contact angles about 10° smaller than those of classical PIPAs. The presence of free slightly diminished the thermal resistance, as evaluated by TGA, but the glass transition temperatures were higher by 20–30°C, with a maximum of 345°C. The mechanical properties of hydroxyl-containing polyisophthalamides were reasonably acceptable, with modulus around 2000MPa and tensile strength up to 60MPa. [Copyright &y& Elsevier]

Abstract: Thermal and representative physico-mechanical properties of newly prepared poly[(ε-caprolactam)-co-(ε-caprolactone)] and poly[(ε-caprolactam)-co-(δ-valerolactone)] copolymers were studied. The copolymers were synthesized by anionic polymerization of ε-caprolactam activated by isocyanate end-capped oligomeric aliphatic polyesters designated as the macroactivators (MAs). Type, concentration and molecular weight of the MAs were varied, which resulted in copolymers with different structure and properties. The impact of the new MAs used in this study on the glass transition temperature and the melting temperature of poly-ε-caprolactam was investigated by DSC. DMTA was used to analyze the effect of copolymerization on the storage modulus (E′) and tan δ of poly-ε-caprolactam. Conventional and high-resolution TGA data revealed that all the synthesized polyesteramides possess good thermal stability. Mechanical properties were studied by notched impact and tensile testing. According to the experimental data the impact toughness increase with the MA content, being six time higher compared to the poly(ε-caprolactam) in the best situation. Water absorption was also considered in relation to the composition of the copolymers. [ABSTRACT FROM AUTHOR]

Abstract: A new phosphorus containing trifluoromethyl-activated bisfluoro B2 monomer has been synthesized successfully by coupling reaction of 4-methoxyphenylphosphonic dichloride and the Grignard salt of 5-bromo-2-fluorobenzotrifluoride. This monomer was converted to linear poly(arylene ether phosphine oxide)s by nucleophilic displacement of the fluorine atom on the benzene ring with several diphenols. The B2 monomer was further demethylated to form an AB2 monomer which on self condensation yielded hyperbranched poly(arylene ether phosphine oxide) with identical phosphorous containing moiety. The products obtained exhibit weight-average molecular weights as high as 600,000gmol−1 in SEC. These linear and hyperbranched poly(arylene ether phosphine oxide)s showed thermal stability as high as 516°C for 10% weight loss in TGA in nitrogen and showed glass transition temperatures up to 253°C in DSC. All the polymers were soluble in a wide range of organic solvents, e.g., CHCl3, THF, NMP and DMF, however, the hb sample showed a significant lower solution viscosity compared to linear samples of similar molar mass. Transparent thin films of linear poly(arylene ether phosphine oxide)s casted from dichloromethane exhibited tensile strengths up to 50MPa, a modulus of elasticity up to 0.95GPa and elongation at break up to 36% depending on their exact repeating unit structures. No free standing films could be prepared from the hb analogue due to the missing entanglements, but stable thin polymer films on silicon wafers with high hydrophobicity were formed which showed water contact angles as high as 91°. [ABSTRACT FROM AUTHOR]

Abstract: New thermoplastic poly(carbonate-urethane) elastomers (TPCUs) were prepared by a one-step melt polymerization from 20–80mol% poly(hexane-1,6-diyl carbonate) diol of as a soft segment, hexane-1,6-diyl diisocyanate and 2,2′-[methylenebis(1,4-phenylenemethylenethio)]diethanol, 3,3′-[methylenebis(1,4-phenylenemethylenethio)]-dipropan-1-ol or 6,6′-[methylenebis(1,4-phenylenemethylenethio)]dihexan-1-ol (H) as new chain extenders at the NCO/OH molar ratio of 1 in the presence of dibutyltin dilaurate as a catalyst. The structures of the TPCUs were examined by FTIR spectroscopy, X-ray diffraction analysis, scanning electron microscopy and atomic force microscopy (AFM). The TPCUs were also characterized by physicochemical, thermal (by differential scanning calorimetry (DSC) and thermogravimetry) and tensile properties as well as Shore A/D hardness. The resulting TPCUs were colorless polymers, showing ordered structures including semicrystalline, with the highest ability to crystallize exhibited by the polymers derived from diol H. The polymers with the soft-segment content of 40–80mol% (56.4–25.7wt% of hard segments) exhibited a microphase separation shown by DSC and AFM. The TPCUs showed tensile strength in the range of 8.8–23.3MPa and elongation at break in the range of 240–670%. [Copyright &y& Elsevier]

Abstract: Five new block copoly(imide siloxane)s have been prepared by reacting two different diamines, 4,4″-bis(p-aminophenoxy)-3,3″-trifluoromethyl terphenyl (APTTFT) and amino-propyl terminated polydimethylsiloxane (APPS), separately with 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride); BPADA. The reactions were conducted by a two pot solution imidization technique. The diamine APTTFT and the dianhydride BPADA composed the hard block segment while APPS and BPADA composed the soft block segment. The soft and hard blocks of different block lengths were generated by different stoichiometric imbalance in two different flasks and the final polymers were obtained by reacting both the blocks together. Different block copoly(imide siloxane)s were prepared on increasing the hard block lengths (DP) from 7 to 12, 18, 23 and 28 and the soft block lengths (DP) from 4 to 6, 8, 10 and 12, respectively. The resulting polymers have been well characterized by NMR, DSC and DMA techniques. The properties of the block copolymers were compared with the analogous random copolymers and homopolyimide prepared without APPS. [Copyright &y& Elsevier]

Abstract: Polyesteramides derived from the cyclic monomers ε-caprolactam and ε-caprolactone have been synthesized by the anionic polymerization and characterized. ε-Caprolactam magnesium bromide was employed as unique initiator giving high yield of copolymer across the whole range of monomer concentrations at 150°C. Owing to a variation of the content of ester and amide component in polyesteramide backbone a large variety of materials having diverse physico-chemical and mechanical properties have been prepared. Materials prepared were examined for mechanical characteristic. Thermal properties were characterized using DSC, temperature modulated DSC, Hi-ResTM TGA and DMA. Viscosity measurements were employed for molecular characterization. [Copyright &y& Elsevier]

Abstract: Blends of recycled poly(ethylene terephthalate) (R-PET) and linear low density polyethylene (LLDPE) were compatibilized with poly(styrene-ethylene/butyldiene-styrene) (SEBS) and maleic anhydride-grafted poly(styrene-ethylene/butyldiene-styrene) (SEBS-g-MA). Effects of compatilizer were evaluated systematically by study of mechanical, thermal and morphology properties together with crystallization behavior of PET. Tensile properties of the blends were improved effectively by the addition of 10wt% SEBS-g-MA, elongation at break and charpy impact strength were increased with the increasing content of compatilizer. SEBS-g-MA is more effectual on mechanical properties of R-PET/LLDPE blends than SEBS. DSC analysis illustrates crystallinities of PET and LLDPE were increased by compatilizer at annealing condition. WAXD and FT-IR spectra show that annealing influences crystallization behavior of PET. Different compatilizer content results in different morphology structure, in particular, higher SEBS-g-MA content can induce the formation of a salami microstructure. [Copyright &y& Elsevier]

Abstract: The relationships between structure and properties have been established for isotactic polypropylene, iPP, homopolymers synthesized by metallocene catalyst systems. These iPPs exhibit different isotacticity degrees and molecular weights, and several thermal treatments during their processing have been applied. The most important factor affecting the structure and properties of these polymers is the isotacticity content. The thermal treatment, i.e., the rate of cooling from the melt, is also important and a clear molecular weight effect has been also found for the sample with lowest M w. These factors affect the thermal properties, the degree of crystallinity and, therefore, the structural parameters and the viscoelastic behavior. A slow cooling from melt favors the formation of the γ phase instead of the α modification. The storage modulus, Young modulus and microhardness values increase as crystallinity does, independently of the origin of this increase: higher isotacticity or application of a slow crystallization from the melt. [Copyright &y& Elsevier]

Abstract: Nano- and micro-composites of poly(l-lactic acid) (PLLA) with various loadings of natural and hexadecylamine-modified montmorillonite were prepared by the solvent casting method to study the effect of nanostructure on the thermomechanical properties of the hybrid materials. The changes on structure and surface of montmorillonite, induced by the ion-exchange modification process, were characterized by X-ray diffraction (XRD) analysis and zeta-potential determination, while the morphology of the hybrids and the dispersion of the clay into the polymer matrix were examined by XRD, transmission electron microscopy and atomic force microscopy. The results showed that, although at low clay content exfoliation dominates, for filler loadings greater than 5wt% both exfoliation and intercalation of the clay filler are observed. Thermal degradation studies of the materials produced using thermogravimetry revealed the introduction of a small amount of organo-modified silicate significantly improves their thermal stability. Differential scanning calorimetry showed the thermal behavior of the polymer matrix strongly depends on the nature and content of the silicate filler. Scanning electron microscopy of the deformed surfaces affirmed a different deformation process mechanism between the two types of composites. [Copyright &y& Elsevier]

Abstract: Fluorinated copolymers are well known for their large range of applications. These applications can be improved by grafting or crosslinking of several agents. The mechanism of crosslinking of hexamethylene diamine and 2,4,4-trimethyl-1,6-hexanediamine is well known and occurs in four different steps. To elaborate a film of commercially available poly(VDF-co-HFP) copolymer crosslinked by 2,4,4-trimethyl-1,6-hexanediamine, a step of press cure under air is necessary. Temperature, time and pressure were optimised by regarding the solubility of the press cured films, the mechanical properties, the swelling rate in methyl ethyl ketone, and the degradation of the films. The best temperature, time and pressure for press cure were 150°C, from 15 to 30min, and 20bars, respectively. Other properties of crosslinked poly(VDF-co-HFP) copolymers containing 10mol.% and 20mol.% of HFP were characterized. First, all films were insoluble in concentrated HCl. Secondly, swelling rates of different amounts of diamine crosslinked copolymers were measured in ethylene carbonate/dimethyl carbonate and in methyl ethyl ketone; it was proved that the higher the molar percentage of diamine, the higher the crosslinking density, so the lower the swelling rate. Concerning thermal properties, glass transition temperature mainly increased when the amount of diamine increased. Thermal stability measurements showed a higher decomposition temperature when the percentage of diamine was very low (5mol.%). Finally, mechanical properties were measured by dynamic mechanical analysis; the storage tensile modulus (E′) of a diamine crosslinked Kynar® copolymer versus temperature exhibited a high drop because Kynar® was a highly amorphous copolymer. Moreover, the higher the amount of diamine, the higher the rubbery modulus. [Copyright &y& Elsevier]

Abstract: The cationic polymerization and physicochemical properties of a biobased epoxy resin, epoxidized castor oil (ECO), initiated by N-benzylpyrazinium hexafluoroantimonate (BPH) and N-benzylquinoxalinium hexafluoroantimonate (BQH) as thermally latent catalysts were studied. As a result, BPH and BQH show an activity at different temperatures in the present systems. The cured ECO/BPH system showed a higher glass transition temperature, a lower coefficient of thermal expansion, and higher thermal stability factors than those of the ECO/BQH system. On the other hand, the mechanical properties of the ECO/BQH system were higher than those of the ECO/BPH system. These have been attributed to the differences in crosslinking level of cured resins, which were induced by the different activity of the latent catalysts. [Copyright &y& Elsevier]

One result of the discovery of homogeneous metallocene stereospecific catalysts is the ability to prepare polypropylene in a stereoblock form in which the isotactic stretches give crystallites acting as temporary crosslinks in an elastomeric network structure. The fact that these elastomers are thermoplastic and thus reprocessible increases the importance of establishing their structure–property relationships. In this report, the dependence of their physical properties on isotactic pentad content, molecular weight, and possible strain-induced crystallization are described. Thermal evaluations and mechanical tests of these materials under oscillatory strain, continuous extension and near-equilibrium uniaxial and biaxial elongation showed that they were multiphase, tough elastomeric materials. Their moduli and tensile strengths increased with increase in % isotactic pentad content and with increase in molecular weight. Equilibrium stress–strain measurements showed the occurrence of strain-induced crystallization in uniaxial, but not in biaxial, deformations. [Copyright &y& Elsevier]

Melt blends of syndiotactic polystyrene (sPS) and poly(p-phenylene sulfide) (PPS) have been prepared by using an internal mixer at 300 °C. The thermal, mechanical and morphological properties of binary blends of sPS with PPS have been investigated in this paper. The thermal and morphological properties show the immiscible binary blend evidences, which have a clear phase separation between the components at all compositions and a lack of adhesion at the interface. According to the X-ray diffraction patterns of blends, the crystalline structure of sPS in the blend is not altered from α form to β form. Indeed, the results for tensile test reveal that there is no synergism of the modulus of elasticity for sPS/PPS blend system. [Copyright &y& Elsevier]

[Display omitted] • A new strategy for preparing GO-SiO 2 hybrids via amino-terminated HBP was developed for the first time. • The HBP on the SiO 2 surface not only reacted better with the groups on GO surface, but also participated in the curing reaction of epoxy resin. • GO-SiO 2 /epoxy composites displayed higher mechanical and thermal properties than that of GO or SiO 2 composites. • The improvement was attributed to the synergistic effect among GO and SiO 2 and the strong interaction with the epoxy matrix. The deposition of nano-silica (SiO 2) on graphene oxide (GO) surface via amino-terminated hyperbranched polymer (HBP) was designed to improve the dispersion and interfacial interaction between GO and epoxy resin. The structures and morphologies of GO and GO-SiO 2 sheets were characterized by FT-IR, XRD, XPS, TG, SEM and TEM. Epoxy composites containing GO and GO-SiO 2 with 0.1 wt% loadings were prepared and systemically investigated. It was indicated that the GO-SiO 2 /epoxy composites displayed higher mechanical and thermal properties than that of GO or SiO 2 composites. For epoxy composites containing 0.1 wt% GO-SiO 2 , the flexural strength increased by 20.57% and 23.58% compared to that of individual GO composites and individual SiO 2 composites, respectively. Furthermore, the reinforcing mechanisms have been also illuminated. This work is expected to be beneficial to the designing of adhesive-bonded composite structures or components. [ABSTRACT FROM AUTHOR]