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11.
J. Ramier L. Chazeau C. Gauthier L. Guy M. N. Bouchereau 《Journal of Polymer Science.Polymer Physics》2006,44(1):143-152
The treatment of nanoscopic silica grafted in the blend during the processing of silica‐filled styrene butadiene rubber was performed with silane, introduced at different concentrations, or at a constant concentration with a given length of alkyl chain. From swelling measurements in water and in solvent, the maximum silane content that can be grafted has been calculated as a function of the length of the silane alkyl chains as well as their efficiency to cover the silica surface. The found values are close to the values found in the literature for grafting in solution. Moreover, a direct correspondence between the length of the silane alkyl chains and their concentration has been deduced. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 143–152, 2006 相似文献
12.
S.H. LiuX.F. Qian J. YinL. Hong X.L. WangZ.K. Zhu 《Journal of solid state chemistry》2002,168(1):259-262
Ag2S nanoparticles in hyperbranched polyurethane matrix were prepared through the in situ reaction with thioacetamide as the sulfur source at room temperature. Transmission electron microscopic analysis revealed a uniform spherical shape for Ag2S nanoparticles, with an average size of about 4-10 nm and a narrow size distribution. X-ray powder diffraction and UV-vis spectroscopy were also used to characterize the obtained nanoparticles 相似文献
13.
Summary Differential scanning calorimetric measurements in the early stage of isothermal crystal growth of polyethylene oxide are
analysed in the light of irreversible thermodynamics. An accurate evaluation of the equilibrium melting temperature is done
by fitting the thermograms obtained at different undercoolings and referring to the activation energy values already known
from the literature.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献
14.
PENG Jian-wen XIAO Chong SONG Qiang PENG Zhong-chao HUANG Ruo-sen YANG Ya-dong TANG Gang 《光谱学与光谱分析》2021,41(12):3901-3908
采用熔融共混技术,将聚磷酸铵(APP)和氢氧化铝(ATH)引入到聚氨酯弹性体(TPU)中,制备了一系列热塑性聚氨酯/聚磷酸铵/氢氧化铝(TPU/APP/ATH)复合材料。采用傅里叶红外光谱(FTIR)、X-射线光电子能谱(XPS)、扫描电镜(SEM)、激光拉曼光谱研究了TPU和阻燃TPU(FR-TPU)复合材料燃烧后炭渣的微观形貌、表面结构、元素组成、键合状态和石墨化程度,结合阻燃性能测试,揭示APP和ATH的协同阻燃机制。SEM分析表明相较于APP与ATH单独使用,TPU/APP/ATH炭层的空洞结构更少,炭渣的致密性更高。XPS分析表明FR-TPU的炭渣中C元素含量相比于纯TPU有所降低,O元素的含量有所上升,其中TPU/APP10/ATH10的C元素含量从88.2%降至69.24%,O元素的含量从8.07%升至17.78%,P和Al元素含量相较于单独添加分别从11.74%和16.36%下降至3.91%和3.31%。在此基础上,通过对C元素的分峰拟合发现TPU炭渣中C—C/C—H,C—O/C—N和CO/CN含量分别为61.05%,35.65%和3.30%;TPU/APP10/ATH10炭渣中三种结构含量分别为45.38%,45.00%和9.63%,说明ATH和APP复配使用有利于C元素形成酯、醚、羰基、羧酸(盐)、酯基等结构。通过对O元素的分峰拟合发现,TPU炭渣中O2/H2O,—O—,O三种结构含量分别为28.75%,44.36%和26.89%;TPU/APP10/ATH10炭渣中O2/H2O,—O—,O三种结构含量分别为44.33%,32.78%和22.89%,说明APP和ATH的加入有利于炭渣中O元素形成O2/H2O结构。通过对N元素的分峰拟合发现,TPU炭渣中—NH—,N结构的N元素含量分别为40.93%和59.07%;TPU/APP10/ATH10中—NH—,N结构的N元素含量分别47.17%和52.83%,说明ATH与APP复配使用促进了—NH—结构的形成。拉曼测试表明,相比于单独使用,APP和ATH复配使用,炭层的石墨化程度更好,致密性更高。以上分析结合阻燃测试可以得出TPU/APP/ATH复合材料阻燃机制:ATH受热分解生成氧化铝,吸收热量并释放大量水蒸气,有效促进APP降解,生成不燃性的氨气和聚磷酸,氨气和水蒸气稀释可燃性气体的浓度。随着温度继续升高,氧化铝可继续与聚磷酸反应生成偏磷酸铝[Al(PO3)3],同步催化聚氨酯基体成炭,形成高度石墨化炭层,石墨化炭层与偏磷酸铝一起覆盖在基体表面,有效抑制燃烧区域物质以及能量的输运,从而达到阻燃目的。 相似文献
15.
Mingli Jiao Kai Yang Wangxi Zhang Wei Pan Ruiwen Zhang Si Xie 《Journal of Macromolecular Science: Physics》2013,52(11):2103-2115
A series of poly(L-lactic acid)/polybutadiene (PLA/PB) biodegradable multiblock elastomers was synthesized and characterized. A two-step process to prepare PLA/PB multiblock elastomers was applied. Melt polymerization was used to prepare poly(L-lactic acid) (PLA) terminated with hydroxyl groups and, at the same time, hydroxyl-terminated polybutadiene (HTPB) and 1,6-hexamethylene diisocyanate (HDI) were employed to synthesize diisocyanate-terminated polybutadiene (ITPB). Then, PLA and ITPB were reacted with different PLA/PB weight ratios. Consequently, a series of PLA/PB biodegradable poly(ester-urethane)s with crosslinked chains was obtained. Swelling characteristics and crosslink density of the crosslinked elastomer were investigated. DMA was applied to characterize its thermal properties. The measurement of mechanical properties showed that a PLA/PB elastomer with adjustable mechanical properties was synthesized. Micromorphology, hydrophobicity, and degradability of the material were also characterized. 相似文献
16.
Sang Hyop Choi Dong Hoon Kim Anjanapura V. Raghu Kakarla Raghava Reddy Hyung-Il Lee Koo Sik Yoon 《Journal of Macromolecular Science: Physics》2013,52(1):197-207
Nanocomposites of waterborne polyurethane (WPU) reinforced with functionalized graphene sheets (FGSs) were effectively prepared by casting from a colloidal dispersion of FGS and WPU, and the morphology and physical properties were examined. The finer aqueous FGS dispersions or WPU with smaller particles yielded nanocomposites with enhanced electrical conductivity and thermal resistance due to finely dispersed FGS. The FGS nucleated the crystallization of the polycaprolactone (PCL) segments in WPU and improved its modulus. However, FGS inhibited crystal growth and deteriorated the tensile properties at high deformation, i.e., tensile strength and elongation at break, because the interaction between FGS and WPU hindered the chain rearrangement of WPU in the nanocomposite. 相似文献
17.
18.
聚氨酯抛光片在透镜高效生产中的应用 总被引:1,自引:0,他引:1
本文对聚氨酯抛光片的性能、特点作了概要介绍,在透镜生产中应用聚氨酯抛光片单块加工及成盘加工的方法分别作了讨论,以及众多的工艺因素作了较为详细的分析,介绍了常出现的光圈异常现象的排除方法,从而达到稳定、高效的目的。 相似文献
19.
We propose a simple friction model for isolated polymer chains on a solid substrate. The chains are pulled at constant velocity
by one end, the other end can be trapped on the solid substrate on localised sites. We focus on the energy dissipation due
to the traps. This simple model leads to nontrivial friction laws, depending on the velocity and the distance between traps.
Some refinements of the model such as the effect of thermal fluctuations are also reported.
Received 20 March 2000 相似文献
20.
V. V. Tereshatov 《Journal of Macromolecular Science: Physics》2015,54(4):365-380
The stress–strain dependences of segmented elastomers based on polyetherurethanes, polyesterurethane ureas, and polybutadieneurethane ureas were investigated. These dependences were adequately described using the generalized approach proposed earlier by the authors for amorphous elastomers. The experimental data obtained for four series of samples with chemical cross-linking confirmed an applicability of this approach for segmented elastomers. Unlike amorphous elastomers, the effective network density value was affected not only by the density of the chemical network, but the contribution of the network formed by the hard domains also needs be taken into account. 相似文献