共查询到20条相似文献,搜索用时 62 毫秒
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综述了低聚合度、部分醇解型聚乙烯醇(PVA-0588)在纺织业、长纤维经纱上浆、印刷业、医药业、建筑业以及其他领域的应用开发,并简介PVA-0588的制法和主要特性。 相似文献
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低聚合度、低醇解度PVA的中间产品PVAc聚合度的研究 总被引:1,自引:0,他引:1
本文研究了聚醋酸乙烯聚合度的调节方法,重点探讨了制取PVC悬浮聚合用分散剂——低聚合度、低醇解度PVA的中间产品低聚合度聚醋酸乙烯的方法。 相似文献
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研究了S-500型低聚合度PVC树脂的合成技术,确定了使用链转移剂合成S-500型PVC树脂的聚合配方和工艺条件。结果表明:S-500型PVC树脂相对分子质量分布集中,颗粒规整度好,粒度分布集中,熔体流动速率较高,加工塑化性能良好。 相似文献
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王元荪 《合成材料老化与应用》2012,(3):55-55
专利申请号:CN200910167753.0公开号:CN101665548申请日:2009.09.25公开日:2010.03.10申请人:四川金路集团股份有限公司本发明公开了一种超低聚合度的PVC树脂及其生产方法。本发明采用聚合方法进行聚合反应,反应温度60~64℃,反应压力小于1.0MPa,在聚合反应开 相似文献
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根据氯乙烯聚合机理,由低温法合成高聚合度聚氯乙烯实验数据,拟合得到平均聚合度与温度、引发剂浓度的关系式:^-P1/{13400exp(-45000/RT)+100exp(-20500/RT)[I]/[M]},向单体、引发剂链边转移常数与温度的关系式:CM=13400exp(-45000/RT),C1=100exp(-20500RT)。 相似文献
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高聚合度的聚醋酸乙烯酯醇解制备聚乙烯醇,由于其相对分子质量较大,所以研究其醇解工艺显得尤为必要.就影响醇解工艺的因素,如醇解温度、醇解时间、催化剂浓度等进行了探讨,得出了高聚合度PVAc醇解最佳工艺. 相似文献
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In this paper, the high value-added (ultra-low degree of polymerization [ULDP]) polyvinyl alcohol (PVA) product was successfully prepared by oxidative chain scission method with sodium hypochlorite as an oxidant. When the molar ratio of PVA to NaClO is not less than 1:1.8, the reaction is stirred for several hours (≥2 h) at a temperature not exceeding 50°C. After precipitation and washing in methanol, PVA with polymerization degree of 38–150 can be obtained after drying. The infrared spectrum (IR) and nuclear magnetic hydrogen spectrum (1H-NMR) test proved that the product obtained by this method is indeed PVA. The results of 1H-NMR also showed that the chain broken has no selectivity and the stereoregularity of hydroxyl group did not change significantly. Through radical quenching experiment and electron paramagnetic resonance (EPR) analysis, it is proved that OCl− is the main active oxide, ·Cl makes the oxidative chain scission process can be realized quickly, and ·OH is an indispensable factor for obtaining ULDP PVA. Under the combined action of these three, high value-added PVA with ULDP was successfully prepared. Additionally, the sodium hypochlorite oxidized the ·OH captured by 5,5-dimethyl-1-pyrroline-n-oxide (DMPO-OH) to 2-hydroxy-5,s-dimethyl-1-pyrroline-N-oxide (HDMPO-OH) in an alkaline environment. 相似文献
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Xinqiu Hong Yongjing Xu Liming Zou Yan Vivian Li Junwei He Jiongxin Zhao 《应用聚合物科学杂志》2021,138(10):49971
Polyvinyl alcohol (PVA) fibers were prepared using PVA with different degree of polymerization (DP) under the same wet spinning process. The effect of the DP of PVA on the structures and properties of PVA and PVA fibers were studied by using nuclear magnetic resonance hydrogen spectroscopy (1H-NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimeter (DSC), thermo gravimetric analysis (TGA), and environmental scanning electron microscope (ESEM). The results showed that DP had little effect on the crystallinity and tacticity of PVA, but had a positive effect on melting temperature, and initial decomposition temperature of PVAs. The hot drawing ratio determined by the spinning process where the PVA fibers could be continuously collected without breaking. The drawing ratio was decreased with an increase of DP, resulting in an increase of the final fiber diameter. The PVA fibers with medium DP and medium size demonstrated high strength and high modulus, but relatively low breaking elongation. It suggested that high DP of PVA was not a guarantee of high strength and high modulus PVA fibers, but rather a primary structure factor. The fiber performance was determined by a comprehensive effect combining a variety of factors including polymer properties and spinning conditions. It provided a guideline for PVA fiber manufacture that the PVAs with different DP require different spinning processes to obtain optimal fiber performance. 相似文献
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用乙醇为溶剂醇解聚醋酸乙酯(PVAc)制备80%醇解度的聚乙烯醇(PVA),采用正交实验法得到最佳制备工艺,用红外光谱对PVA进行了表征。结果表明:红外光谱表征PVA的特征波数为3 378 cm-1。在含碱量0.38%,含水量1.2%,加酸时间50 m in的最佳醇解条件下,可得到醇解度为80.6%的PVA,其质量指标达到日本进口分散剂KH-20要求。 相似文献
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Ken Yuki Toshiaki Sato Hitoshi Maruyama Junnosuke Yamauchi Takuji Okaya 《Polymer International》1993,30(4):513-517
Emulsion polymerization of styrene (St) and vinyl acetate (VAc) in the presence of conventional polyvinyl alcohol (PVA), PVA modified with a terminal alkyl group or PVA modified with a terminal thiol group (HS-PVA) was compared. Whereas stable PVAc latexes were obtained, a stable PSt latex was obtained only in the case of HS-PVA. From the adsorption isotherms of these PVAs on the surface of PVAc and PSt latex particles, as well as the grafting efficiencies of VAc and St onto HS-PVA in relation to the stability of the polymerization process, the role of PVA in the emulsion polymerization was discussed. 相似文献
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