共查询到20条相似文献,搜索用时 62 毫秒
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共沉积技术制备了聚乳酸(PLA)/聚氧化乙烯(PEO)共混物,通过DMA和相差显微镜考察了共混物的相行为。用DSC研究了PLA/PEO共混物的结晶形貌及其动力学,由于部分相容的熔融态PEO提高了PLA分子链的运动能力,导致显著促进了PLA的结晶速率;结合偏光显微镜(POM)观察分析,结晶速率的提高源于结晶生长速率的促进,而且在低的结晶温度时的结晶速率的增加更为明显。 相似文献
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研究了表面活性剂聚氧乙烯山梨醇脂肪酸酯(吐温-80)与脂质膜间的相互作用,运用浊度测定、DSC、1HNMR等分析手段验证了脂质膜的立体稳定结构。结果表明:聚氧乙烯山梨醇脂肪酸酯在水相与脂质相间分配达到饱和时的质量分数为w(聚氧乙烯山梨醇脂肪酸酯)=1 3%,与脂质膜开始增溶成混合胶团时的质量分数为w(聚氧乙烯山梨醇脂肪酸酯)=2 6%。当Re〔表示吐温-80与卵磷脂的摩尔比值,即n(吐温-80)/n(卵磷脂)〕<0 5时,表面活性剂单体在溶液和脂质双层膜中分配,溶液中表面活性剂单体和囊泡并存,脂质双层囊泡膨胀,粒径逐渐增大,形成一个肿胀的脂质囊泡;当0 5相似文献
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水溶性氨基聚硅氧烷织物柔软剂的研究 总被引:1,自引:0,他引:1
以氨基分布均匀的反应性氨乙基氨丙基硅油和聚氧乙烯甲基缩水甘油醚为原料,通过开环反应,合成了可用于织物柔软整理的水溶性氨基聚硅氧烷,整理后的织物具有柔软的手感、较好的白度和吸水性。确定了最佳合成条件:聚氧乙烯甲基缩水甘油醚与反应性氨乙基氨丙基硅油摩尔比为7.2,w(异丙醇)=1(相对于聚氧乙烯甲基缩水甘油醚和氨基硅油的总质量),反应温度为80℃,反应时间为5h。 相似文献
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Jose Román Galdámez Adam T. Jones Ronald P. Danner 《Polymer Engineering and Science》2015,55(6):1459-1462
There are indications in the literature that the devolatilization of some polymers, particularly polyethylene, can be enhanced by the addition of water, generally in the form of steam. In this study three different experimental methods were used with three different solvent–polyethylene systems to evaluate this effect. The results indicated that no measureable differences were found in either the solubility or the diffusivity of the systems between the dry or wet polymer samples. POLYM. ENG. SCI., 55:1459–1462, 2015. © 2015 Society of Plastics Engineers 相似文献
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Zhenhu Cao Pingan Song Zhengping Fang Yuanyuan Xu Yan Zhang Zhenghong Guo 《应用聚合物科学杂志》2012,126(5):1546-1555
A facile method to encapsulate the reduced graphene oxide (RGO) sheets physically with polyethylene (PE) wax was developed. The graphene oxide sheets were first wrapped with polyethylene wax, and reduced by hydrazine hydrate. The structure of the wrapped RGO was confirmed by means of Fourier transform infrared spectroscopy, X‐ray diffraction (XRD), and Raman spectroscopy. The PE wax‐wrapped RGO sheets were melt blended with PE to prepare PE/RGO nanocomposites. Transmission electron microscopy and XRD studies showed that this method could provide uniform dispersion of RGO sheets in the PE matrix. Scanning electron microscopy and Raman spectroscopy indicated that there was a strong interfacial interaction between the PE wax‐wrapped RGO sheets and PE matrix. Addition of 1 wt % RGO sheets in PE matrix led to a 48% increment in the yield stress and 118% increment in the Young's modulus, respectively. However, the elongation at break decreased with increasing RGO sheets loading content. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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Polymers like LDPE can be modified by applying a shearing process for an extended period. As a result the melt elasticity is reduced, as evidenced by the decrease in extrudate (die) swell at the exit of a capillary and onset of melt fracture. Melt viscosity was also slightly reduced; melt flow index (measured in short capillary) is highly increased. At the same time, melt density rises. All these parameters vary mostly for LDPE grades that exhibit the highest degree of long-chain branching. It was confirmed that the intrinsic viscosisty of the polymer samples was essentially unaffected, so that chain scission may be ruled out. Moreover, the process itself is shown to be reversible as the initial parameters were recovered by special treatment, due to heating or solvation. The mechanism of shear modification is believed to consist of disentanglement of temporary couplings betwen long branches. The practical utilization of this process will be pursued, as well as the scientific understanding of structuring entangled branched chains. 相似文献
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通过溶剂浇注法制备了丁腈橡胶/聚氧乙烯(NBR/PEO)共混物,通过接触角测试、傅里叶变换红外光谱分析和差示扫描量热分析,研究了NBR和PEO相互作用对PEO结晶性能的影响。结果表明,NBR/PEO共混物的表面能和附着功分别为8.80 mJ/m2和56.90 mJ/m2,两者之间具有一定的相容性;NBR中的腈基和PEO中的醚基之间并没有相互作用,两者之间具有一定的相容性,是由非极性部分贡献;NBR/PEO共混体系中随着PEO含量的减少,PEO分子链采取旁式构象的结晶结构增多,并使PEO的结晶度和结晶熔融温度明显降低,在PEO含量为5份时,NBR/PEO共混体系中PEO结晶度和结晶熔融温度分别下降80%和10.5℃,NBR的加入明显抑制了PEO的结晶。 相似文献
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An absorption model of gases in semicrystalline polymer was built that was based on the activity coefficient theory in polymer solution and associated with crystallinity dependent on temperature. The solubility of ethylene, isopentane, and n‐hexane in three types of polyethylene (PE) were obtained by the use of a pressure‐decay method at temperatures of 333–363 K and pressures of up to 2 MPa, 80–300 KPa, and 19–100 KPa, respectively. Experimental data from three gases in each PE sample were used for the single‐parameter fitting, and fitting error was within about 12%. It was found that a single parameter was merely dependent on the properties of PE used. It was shown that, unlike with the Flory–Huggins model and the UNIFAC–M‐H method, correlation between the crystallinity of the semicrystalline polymer and temperature had to be taken into account in order for the solubility data of alkane, olefin, and aromatic hydrocarbons in polyethylene to fit well, especially in the temperature range near the melting point of the polymer. The four free‐energy contributions to the total gas activity were experimentally determined to be about 47%–60% combined, the free‐volume contribution about 12%–25%, and the elastic effect about 22%–35%, but the interactional contribution was zero. The contributions changed with the size of the gas molecules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1737–1744, 2007 相似文献
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介稳区宽度(MSZW)是结晶过程设计的重要参数,为了得到高纯度大颗粒的烟酸晶体,应将结晶条件控制在介稳区内。测定烟酸在293.15—323.15 K下的溶解度,并用Apelblet经验方程关联,与实验值相比有较好的拟合效果,相对偏差在0.66%以下,平均偏差为0.27%;以溶解度数据为基础,计算了烟酸的溶解热力学参数。另外,通过聚焦光速反射测量(FBRM)技术测定烟酸的介稳区宽度,研究了降温速率、搅拌速率和晶种加入量对介稳区宽度的影响,研究发现,较小的降温速率、较大的搅拌速率以及加入晶种都会使介稳区宽度变窄;适当增大晶种数目,可以有效调节介稳区。溶解度及介稳区的测定,为生产过程工艺放大以及结晶器的设计提供数据支撑。 相似文献