Novel Method for Preparation of Low Molecular Weight Natural Rubber Latex
Novel Method for Preparation of Low Molecular Weight Natural Rubber Latex
复制标题
低分子量天然胶乳制备新方法
DOI：
10.5254/1.3538505
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发表时间：
1998
影响因子：
1.5
通讯作者：
Yasuyuki Tanaka
中科院分区：
文献类型：
--
作者：
J. Tangpakdee;Megumi Mizokoshi;A. Endo;Yasuyuki Tanaka
摘要 在 1 份 K2S2O8 和 15 份丙醛存在下，在 60 ℃ 下振荡氧化降解脱蛋白天然橡胶（DPNR）胶乳，制备低分子量天然橡胶（LNR）和 LNR 胶乳。仅含有 K2S2O8 的 DPNR 的特性粘度 [η] 在 2 小时后从 7.2 降至 5.5，然后在 3 小时后增加至 6.5。添加丙醛后，DPNR 的 LNR 的 [η] 值在反应 5 小时后显着下降，[η] 约为 0.5，而高氨天然橡胶 (HANR) 胶乳的 [η] 略有下降。胶乳的浓度和用于稳定胶乳的表面活性剂的种类对DPNR胶乳的降解率影响不大。 LNR胶乳以胶乳形式稳定，并且由胶乳凝固的干燥橡胶是透明且无色的。通过 NMR 和分子量分析测定，LNR 是一种两端含有醛基和酮基的遥爪聚合物。
Abstract Low molecular-weight natural rubber (LNR) and LNR latex was prepared by oxidative degradation of de-proteinized natural rubber (DPNR) latex in the presence of 1 phr of K2S2O8 and 15 phr of propanal, by shaking at 60 °C. The intrinsic viscosity [η] of DPNR with only K2S2O8 decreased from 7.2 to 5.5 after 2 h and then increased to 6.5 after 3 h. By the addition of propanal, DPNR showed a significant decrease in the [η] value of LNR with [η] of about 0.5 after 5 h of the reaction, while rubber from high-ammonia natural rubber (HANR) latex showed a slight decrease in [η]. The concentration of latex and the kind of surfactant used for stabilizing the latex had little effect on the degradation rate of DPNR latex. The LNR latex is stable as the latex form and the dried rubber coagulated from latex is transparent and colorless. The LNR was a telechelic polymer containing aldehyde and ketone groups at both terminals as determined by NMR and molecular weight analyses.