稀土成核剂WBG-Ⅱ对等规聚丁烯-1结晶行为的影响  

Effects of rare earth nucleating agent WBG-Ⅱon crystallization behaviors of isotactic polybutene-1

作　　者：李治岐 李景庆[1] 蒋世春[1] LI Zhiqi;LI Jingqing;JIANG Shichun(School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学材料科学与工程学院,天津300350

出　　处：《分子科学学报》2024年第1期39-45,共7页Journal of Molecular Science

基　　金：This work was financially supported by the National Natural Science Foundation of China(51673147 and 51573131).

摘　　要：通过熔融共混将稀土成核剂WBG-Ⅱ引入等规聚丁烯-1(iPB-1),用广角X射线衍射(WAXD)、差示扫描量热(DSC)、偏光显微镜(POM)对iPB-1结晶行为进行了分析,结果显示,WBG-Ⅱ引入未改变iPB-1熔融结晶得到的晶型,仍为晶型Ⅱ;随着WBG-Ⅱ用量增加,iPB-1结晶温度T_(c,peak)、晶型Ⅱ熔点T_(m),Ⅱ和结晶度X_(c),Ⅱ均先升高后趋于平缓,WBG-Ⅱ引入促进了iPB-1熔融结晶,但用量更多时促进作用减弱;在相同等温结晶温度T_(c)下,WBG-Ⅱ引入明显缩短了iPB-1半结晶时间t_(1/2),提高了iPB-1球晶径向生长速率G,加快了iPB-1等温结晶动力学,且随T_(c)升高该加快作用减弱。iPB-1熔融结晶为晶型Ⅱ的过程中,需iPB-1熔体中无规线团构象转变为11/3螺旋构象,而WBG-Ⅱ引入iPB-1后可避免其在降温过程中熔融结晶为晶型Ⅱ的临界降温速率φc升高,表明WBG-Ⅱ可促进iPB-1链构象调整能力从而弱化iPB-1“强熔体”特点。所得结果为理解高分子结晶过程并为iPB-1成核剂的研究开发提供了思路。Rare earth nucleating agent WBG-Ⅱwas selected and melt blended into isotactic polybutene-1(iPB-1).The effects of WBG-Ⅱon crystallization behaviors and crystalline structures of iPB-1 were studied by differential scanning calorimetry(DSC),wide angle X-ray diffractometer(WAXD)and polarizing microscope(POM).The results showed that incorporation of WBG-Ⅱinto iPB-1 does not affect the melt as-crystallized crystal form of form Ⅱ but with increasing crystallization temperature T_(c.peak),melting point Tm.I and crystallinity XeI of iPB-1 form Ⅱ,especially at a low WBG-Ⅱcontent.With more WBG-Ⅱincorporated,the Te.peak,T_(m,Ⅱ) and X_(c,Ⅱ) all increased slowly to a plateau,showing a decreasing promotion effect on iPB-1 melt crystallization.Under the same isothermal crystallization temperature T_(c),incorporation of WBG-Ⅱresulted in shorter half crystallization time t_(1/2) and higher spherulite radius growth rate G,proving the promotion effect on iPB-1 melt as-crystallization into form II.With T,increasing,the promotion effect weakens.For iPB-1 melt crystallization into form Ⅱ,the random coils of iPB-1 in the melt needs to transit into 11/3 helices.The promotion effect of WBG-Ⅱon iPB-1 crystallization into formⅡmeans WBG-Ⅱincorporation favors the transition from random coils to 11/3 helices of iPB-1,resulting a needed critical cooling rate p.to avoid iPB-1 crystallization while cooling a melt to the glass transition temperature Tg.The enhanced iPB-1 chain conformation adjustment ability weakens the"strong melt"characteristics of iPB-l.The results would shed lights on understanding of polymer crystallization as well as on research and development of iPB-1 nucleating agents.

关 键 词：等规聚丁烯-1 熔融结晶 稀土成核剂 WBG-Ⅱ 

分 类 号：TQ325.15[化学工程—合成树脂塑料工业]