共查询到19条相似文献,搜索用时 93 毫秒
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以甘油为增塑剂,通过甘油对PVA的熔融和结晶行为的影响,研究聚乙烯醇的塑化特性及塑化机理,为实现聚乙烯醇熔融加工提供实验和理论依据。分别配比样品,将各样品在电热高混机中混匀,混炼温度为80℃。然后在密炼机中混合10 min,转速为45 r/min。取出样品进行红外分析、DSC图测试、X射线衍射分析、流变曲线测定等表征与测试。得到出甘油可以降低熔点,这是因为甘油能提高聚乙烯醇的链段活动性、减小结晶区域。但是甘油的使用量不易过大,否则其塑化效果会因为发生相分离而急剧降低。 相似文献
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通过聚乙烯醇(PVA)热塑化加工工艺,采用木糖醇/丙三醇二元复配增塑剂,制备了一系列热塑性聚乙烯醇(TPVA)。研究了木糖醇与丙三醇质量比对TPVA的熔融结晶行为、晶体结构、热稳定性、加工流动性、表观黏度、黄色指数及拉伸性能的影响。结果表明:使用该二元复配增塑剂制备的TPVA热稳定性及拉伸性能明显好于基于单组分丙三醇增塑的TPVA;复配增塑剂中丙三醇比例越高,TPVA的加工流动性越好,熔点、结晶度、微晶尺寸越低;PVA、木糖醇、丙三醇质量分数分别为75.00%,6.25%,18.75%时,TPVA的黄色指数最低,热稳定性及拉伸性能优异,且加工流动性好。 相似文献
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《分离科学与技术》2012,47(6):1357-1360
Abstract Lithium chloride can be recovered from brines by liquid-liquid extraction with alcohols such as n-butanol or isoamyl alcohol as well as by precipitation of the lithium aluminate complex (1–3). In most cases, however, certain amounts of magnesium chloride and calcium chloride are coextracted. In order to obtain pure lithium chloride, separation of alkaline earth compounds by special precipitation (4) or extraction procedures (5) is necessary. On the other side, coextraction of alkaline earth chlorides with alcohols can be suppressed by the addition of ammonia (6) or urea (7). For the separation of lithium from magnesium and sodium, extraction with mixtures of butanol and hexanediols is also recommended (8). 相似文献
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通过溶液浇铸法制备了纤维素纳米纤丝(CNFs)/聚乙烯醇(PVA)复合材料,利用TG、DSC、DMA等方法考察了CNFs对PVA热性能与力学性能的影响。结果表明:CNFs的加入提高了PVA的结晶度与熔点,但随着CNFs含量的增加,由于CNFs与PVA之间存在较强的氢键作用,限制了PVA分子链的运动,使得PVA的熔点与结晶度略有下降;CNFs的加入使得PVA的玻璃化转变温度、拉伸强度与弹性模量提高,添加2%CNFs的PVA复合材料的拉伸强度与弹性模量均达到最大值,分别较纯PVA提升了28.9%与14.1%。 相似文献
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The melting and crystallization behavior of polyvinyl alcohol (PVA) were examined as a function of plasticizer amount. The melting temperature (Tm) of PVA decreased with increasing the amount of glycerin. The effect of a plasticizer rapidly diminished when the phase separation of glycerin in PVA occurred. In addition, the crystallization peak temperature (Tc) of a fully hydrolysed PVA was reduced, and the maximum crystallization rate (Kmax) was retarded, and the crystallite size distribution (ω1/2) was widened. However, the crystallization behavior (Tc, Kmax, ω1/2) of a partially hydrolysed PVA could be disregarded compared with a fully hydrolysed PVA. The thermal history did not affect the crystallization behavior of a fully hydrolysed PVA, but largely affected that of a partially hydrolysed PVA. In a fully hydrolysed PVA / a partially hydrolysed PVA blend system, two Tm peaks appeared, and the concurrent crystallization occurred. 相似文献
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丁腈橡胶/PVC型动态硫化热塑性弹性体性能研究 总被引:7,自引:0,他引:7
利用开炼机,通过动态硫化法制成的共混物丁腈橡胶/PVC型热塑性弹性体(TPE),经透射电镜观察,呈现出明显的两相结构,交联的丁腈橡胶分散相分散于PVC连续相中。共混物的力学性能受硫化体系和加工条件的影响。永久压缩变形、永久拉伸断裂变形、耐油等主要性能均优于简单机械共混物。 相似文献
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论文研究了工业碳酸锂的添加量对釉的熔融特性,热膨胀及晶相组成的。研究得出:当其加入量不超过一定值时,其添加量与釉的熔融特性之间有良好的线性关系。碳酸锂的加入不仅能显著地降低釉的成熟温度及高温粘度,而且能较大的降低其热膨胀系数。 相似文献
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综述了PVC树脂国内外发展概况,国内产需平衡、进出口及“八五”发展情况。分析了国内PVC制品生产、使用及发展前景,对1992年PVC市场进行了预测,并提出了改进建议。 相似文献
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