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91.
92.
《Polymer》2014,55(26):6960-6966
The crystallization behavior of poly(β-propiolactone)-block-polyethylene (PPL-b-PE) copolymers with high PE crystallinities χPE (>0.30) has been examined using time-resolved synchrotron small-angle X-ray scattering and Fourier transform infrared spectroscopy, where the PE block crystallized first and subsequently the PPL block crystallized on quenching from a strongly segregated melt. The crystallization of PE blocks destroyed the lamellar microdomain structure (LMS) existing in the melt to form the crystalline lamellar morphology (CLM), and then PPL blocks crystallized within CLM. This morphology formation was compared to our previous results for the crystallization of PPL-b-PE copolymers with low χPE (0.12 < χPE < 0.26), where the crystallizability of PE blocks was not sufficiently large to destroy LMS. As a result, PE blocks crystallized promptly within LMS to reinforce and stabilize it against the subsequent crystallization of PPL blocks, yielding the confined crystallization of both blocks within LMS. We summarize these results including the case of χPE = 0, and propose three mechanisms of morphology formation occurring in PPL-b-PE copolymers according to χPE (i.e., high, low, or zero). 相似文献
93.
Synthesis and properties of bromide‐ functionalized poly(isobutylene‐co‐p‐ methylstyrene) random copolymer 下载免费PDF全文
Yi Xie Jin‐jie Chang Yi‐bo Wu Dan Yang Hao Wang Tao Zhang Shu‐xin Li Wen‐li Guo 《Polymer International》2017,66(3):468-476
Poly(isobutylene‐co‐p‐methylstyrene) (IB/p‐MS) random copolymer is a new generation of polyisobutylene‐based elastomers. The cationic copolymerization of IB with p‐MS was thoroughly examined by using 2‐chloro‐2,4,4‐trimethylpentane/ethylaluminiumsesquichloride/electron donor as initiating system. IB/p‐MS random copolymers with high molecular weight were obtained at elevated temperature through the addition of ethyl acetate; the reaction proceeded in a mildly exothermic manner. Although the reactivity ratios of comonomer pairs differ by close to an order of magnitude, p‐MS was uniformly distributed in the chains. IB/p‐MS random copolymer can be brominated by adding molecular bromine into the copolymer solution, thereby yielding a completely saturated polymer backbone with a chemically reactive site. The types and selection of appropriate vulcanization systems for bromide‐functionalized IB/p‐MS random copolymers are also discussed. © 2016 Society of Chemical Industry 相似文献
94.
两亲聚合物对湿法磷酸的助滤性能及机理研究 总被引:1,自引:0,他引:1
以实验室自制单体A、丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)为原料,过硫酸盐氧化还原体系为引发剂,采用水溶液共聚法合成一种用于湿法磷酸助滤的两亲聚合物PADA-10。对所得聚合物的助滤性能进行研究,结果表明:磷酸料浆体系中加入PADA-10后,过滤速度提高了约4.3倍,滤饼水分降低了约10.8%。对PADA-10助滤机理的初步探究结果表明:PADA-10能在一定pH值范围内中和磷石膏表面电荷,使磷石膏微晶絮凝成团,添加PADA-10后滤饼的孔隙率增加;同时,PADA-10能增强磷石膏颗粒的疏水性,使磷酸滤液表面张力降低了5.2 mN/m,磷石膏表面接触角增大了3.4°。 相似文献
95.
Xuefeng Li Jingfang Zhang Xingping Zhou Chuan Lu Xiantao Tong Guoxing He Xiaqin Wang 《应用聚合物科学杂志》2012,126(1):110-115
Core‐shell fluoroacrylate copolymer latex was synthesized via semicontinuous seed emulsion polymerization, in which ethyl acrylate was utilized to prepare core, and methyl methacrylate, butyl acrylate, methacrylate acid, and hexafluorobutyl methacrylate were employed to constitute the shell. So the yielded latex particles had the soft core and hard shell. Multifunction and low viscosity of the latex had been applied as the binder of latex inks. The ζ potential showed that the latex particles had high thermodynamic stability. The latex and latex inks exhibited viscosity plateau of Newtonian fluid behaviors. Rheological tests revealed that viscous behaviors dominated in the latex and latex inks. However, there was some interaction among the latex and pigment particles. The hydrophobicity of the cast films of the latex increased with the amount of the fluoroacrylate monomer. Fluorine tended to migrate to the interface between the cast film and air. Therefore, the hydrophobicity was derived from the fluorine enrichment phenomena on the top side of the cast films. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
96.
Wei Zou Xiaozhou Cai Jianwen Li Xinyi Dai Haiquan Zhang Aijun Zhou Jingze Li Lijun Song Tomokazu Iyoda 《Surface & coatings technology》2012,206(22):4634-4638
Selective deposition of Ag onto nanostructured block copolymer film template of poly(ethylene oxide) and poly(methacrylate) with azobenzene mesogen (PEO-b-PMA(Az)) has been done by thermal evaporation technique. A hexagonally arranged pattern or ordered strip structure of the PEO nanocylinders dispersed in the PMA(Az) matrix appears on the pure copolymer film surface after thermal annealing at 140 °C or 110 °C, respectively. Atomic force microscopy confirms that the deposited Ag atoms prefer to wet PMA(Az) matrix domains on the film surface, and finally aggregate into discrete nanoparticles in both cases. An ordered porous metallic layer is created on the hexagonally patterned copolymer template surface due to the preferential interaction of Ag toward the PMA(Az) phase. Alternatively, ordered array of metallic chains is formed on the template featured with strip structure. While the nominal layer thickness of the deposited Ag is 50 nm, the ordered metallic nanostructure disappears, indicating the host copolymer template cannot guide the spatial distribution of the deposited metal any more. 相似文献
97.
One‐pot synthesis of {Mo6I8}4+‐doped polystyrene microspheres via a free radical dispersion copolymerisation reaction 下载免费PDF全文
Natalya A Vorotnikova Mariya V Edeleva Olga G Kurskaya Konstantin A Brylev Alexander M Shestopalov Yuri V Mironov Andrew J Sutherland Olga A Efremova Michael A Shestopalov 《Polymer International》2017,66(12):1906-1912
Molybdenum octahedral clusters, when incorporated into an appropriate polymer matrix, are considered as promising agents for a range of biological applications. This work describes the one‐pot synthesis, morphology and cellular toxicity of nano‐sized polystyrene beads doped with luminescent cluster complexes [{Mo6X8}(NO3)6]2? (X = Cl, Br or I). Specifically, the particles were obtained by free radical dispersion copolymerisation of styrene and methacrylic acid or 4‐vinylpyridine in the presence of the cluster complexes. The effects of the cluster loading in the reaction mixture on both the content of the final material and number‐average molar mass of the copolymers were evaluated. © 2017 Society of Chemical Industry 相似文献
98.
This study is novel to report the utilization of molasses for the production of polyhydroxy propionate-co-hydroxy dodecanoate-co-hydroxy octadecanoate from Pseudomonas sp. LDC-5 as prospective biomaterial. Thermal analysis revealed its potential for thermal permanence and melt processing. 3T3 fibroblasts were cultured on these different scaffolds and their proliferation was compared. Giemsa and acridine orange/ethidium bromide staining revealed that there was no distinct change in morphology. Polyhydroxyalkanoate:poly ethylene glycol blend was found to be the most promising for extracellular matrix secretion, a key thrust function of 3D culture. Lactate dehydrogenase assay indicated the membrane integrity. DNA fragmentation analysis showed that the scaffold did not damage DNA. Thus the prepared scaffold can serve as a promising biomaterial. 相似文献
99.
《Journal of Industrial and Engineering Chemistry》2014,20(2):419-425
The copolymerization of MMA with ethylene was promoted by metallocene complex in the presence of initiator tetra(2,3-epoxy propoxy)silane (Is), reducing agent Zn and cocatalyst MAO, combining free radical polymerization with coordination polymerization via sequential monomer addition strategy in one-pot to produce 4-arms hydroxy-functionalized PMMA-b-PE. The effects of polymerization conditions such as temperature, time, ethylene pressure and Al/Ti molar ratio on the polymerization performance were investigated. 4-Arms hydroxy-functionalized PMMA-b-PE was obtained by solvent extraction and determined by GPC, MALLS, DSC, FT-IR, WAXD and 1H(13C) NMR. The DSC result indicated that the 4-arms hydroxy-functionalized PMMA-b-PE had one Tg at 87.0 °C and one Tm at 117.0 °C which attributed to Tg of PMMA segment and Tm of PE segment, respectively. The microstructure of 4-arms hydroxy-functionalized PMMA-b-PE was further confirmed by WAXD, FT-IR, and 13C NMR analysis. These results demonstrated that the obtained 4-arms block copolymer consisted of PMMA segment and crystalline PE segment. 相似文献
100.