分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-04-06
摘要: A soft segment free thermoplastic polyester elastomer is fabricated by controlling the stereochemical structure of molecular chains with the utilization of the cis 1,4-cyclohexylene ring moiety (cis-CHRM) in poly(butylene 1,4-cyclohexanedicarboxylate) (PB
分类: 材料科学 >> 材料科学(综合) 提交时间: 2017-03-30
摘要: A soft segment free thermoplastic polyester elastomer is fabricated by controlling the stereochemical structure of molecular chains with the utilization of the cis 1,4-cyclohexylene ring moiety (cis-CHRM) in poly(butylene 1,4-cyclohexanedicarboxylate) (PB
分类: 材料科学 >> 材料科学(综合) 提交时间: 2017-03-30
摘要: A soft segment free thermoplastic polyester elastomer is fabricated by controlling the stereochemical structure of molecular chains with the utilization of the cis 1,4-cyclohexylene ring moiety (cis-CHRM) in poly(butylene 1,4-cyclohexanedicarboxylate) (PB
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: Thermal-induced gelation and phase separation was investigated in PAN/DMSO/H2O semidilute solutions utilizing rheological and optical methods. The incipient precipitation temperature, where a distinct decrease in relative light transmittance occurred, was considered as the cloud point (CP). Phase sepa- ration mechanism of nucleation and growth was confirmed by various ramp rates experiments and viscoelastic evolution pattern. On the other hand, the validity of ChamboneWinter model was evaluated in these blends and used to measure the critical gel point (GP). It was found that in the accessible temperature regions CP was always higher than GP, and phase boundaries were constructed accordingly. What's more, the absolute complex viscosity h0 at a low frequency also showed transition points during temperature decreasing experiments, which mostly located between CPs and GPs. The gelation mech- anisms with and without phase separation were proposed and the effect of the two transitions on the structures of the ternary blends were shown by SEM pictures.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: A biobased monofunctional compatibilizer (called Epicard) is first synthesized by the reaction of cardanol with epichlorohydrin as confirmed by Fourier transform infrared and 1H NMR. Subsequently, biosourced polymers, polylactide (PLA) and starch, are melt-blended by a twin-screw extruder with Epicard. Confirmed by the measurements of contact angle and 1H nuclear magnetic resonance of the extracted starches from PLA/starch/Epicard blends, the Epicard only possesses a monoepoxy group to mainly react with starch and then increased the hydrophobicity of the starches during the melt-blending process. As a result, an obvious improvement to the interfacial adhesion between starch and PLA is observed by the scanning electron microscopy. Furthermore, the tensile properties of PLA/starch blends are effectively improved with the addition of Epicard. This study suggests a simple but effective material technique by utilizing a novel plant oil modifier to increase interfacial adhesion in fabricating fully biobased PLA/starch blends with superior tensile properties.
提交时间: 2017-05-02
摘要: In this manuscript, a toughened PLA/nanosilica composite with good storage stability was obtained in the presence of the epoxidized soybean oil [ESO]. The composite was fabricated via a twin-screw extruder, and characterized by the FTIR, selective distrib
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: This paper reported the synthesis of bio-based unsaturated poly(ester- urethane)s via a nonisocyanate route, by metal-catalyzed melt poly- condensation of itaconic acid with urethanediols. Three novel types of bio-based unsaturated poly(ester-urethane)s, namely, poly- (urethanediol 2-itaconic acid), poly(urethanediol 4-itaconic acid) and poly(urethanediol 6-itaconic acid) (poly(U2-IA), poly(U4-IA) and poly (U6-IA) for short code, respectively), were prepared by a green synthetic route. The urethane linkage was formed by the reaction of two equivalent of ethylene carbonate with 1,6-hexanediamine, 1,4- butanediamine and 1,2-ethanediamine to form urethanediols. The urethanediols underwent polymerization with itaconic acid (IA) in the presence of metal catalyst dibutyltin dilaurate (DBTL) to produce low- molecular-weight bio-based unsaturated polyurethanes. Then, these bio-based unsaturated poly(ester-urethane)s were formulated with free radical photoinitiator and curing promoter to prepare UV curable polyurethane systems. After UV curing, the tensile properties, thermal properties and general coating properties of the three UV-cured polyurethane films were similar to that of UV cured polyurethane films prepared by polyurethane-acrylate (PUA). The results suggested that the obtained bio-based unsaturated polyurethanes could serve as coating materials.