聚乙烯-g-聚苯乙烯对线性低密度聚乙烯/聚苯乙烯共混物机械性能和发泡行为的影响

doi:10.11944/j.issn.1000-0518.2016.07.160155

摘要/Abstract

摘要：

以通过开环易位聚合、加氢反应和原子转移自由基聚合技术结合制备的聚乙烯-g-聚苯乙烯(PE-g-PS)作为增容剂,研究了加入不同PS支链长度的PE-g-PS对于线性低密度聚乙烯/聚苯乙烯(LLDPE/PS)共混物的机械性能和发泡行为的影响。以典型组成m(LLDPE):m(PS)=70:30共混物为例,考察了PE-g-PS对共混物拉伸性能的影响。相对于二元共混物,增容剂的加入使得断裂伸长率、拉伸强度和屈服强度皆提高,且含长PS支链的增容体系提高更明显。采用超临界CO₂釜式发泡工艺,考察了PE-g-PS中PS支链长度对共混物发泡行为的影响。结果表明,相对于短PS支链体系,加入PE-g-PS_1.59k(PS相对分子质量为1590)后的泡孔结构更加均一,完全没有“缝隙”形貌的出现。当发泡温度降至80 ℃时,即使存在LLDPE发泡空间限制作用(LLDPE无法发泡),加入支链长度更长的PE-g-PS_1.59k后泡孔分布也更加均一。

关键词: 线性低密度聚乙烯/聚苯乙烯共混物, 增容剂, 机械性能, 釜式发泡, 支链长度

Abstract:

Polyethylene-g-polystyrene(PE-g-PS) copolymers, which were synthesized by the combination of ring-opening metathesis polymerization(ROMP), hydrogenation and atom transfer radical polymerization(ATRP) method, were utilized to compatibilize linear low density polyethylene/polystyrene(LLDPE/PS) blends. Using the LLDPE/PS blend in mass ratio of 70:30 as example, the effect of introduction of PE-g-PS on the mechanical properties was investigated. Compared to binary blends, elongation at break, tensile strength and yield strength are improved when the PE-g-PS is introduced. Utilizing PE-g-PS_0.34k(the subscript 0.34k represents a relative molecular mass of PS is 340) and PE-g-PS_1.59k as compatibilizers, the influence of PS branch length on foaming behavior of LLDPE/PS blends was investigated in a batch foaming process with supercritical carbon dioxide as physical foaming agent. Compared to the case containing PE-g-PS_0.34k, the cellular structure of the foamed blends becomes much more uniform and no large gap appeares with the addition of PE-g-PS_1.59k. When the foaming temperature is lowered to 80 ℃, confined effect of LLDPE solid around exists, much more uniform cellular structure also appears as PE-g-PS_1.59k is introduced.

Key words: linear low density polyethylene/polystyrene blends, compatibilizer, mechanical properties, batch foaming, branch length

张光春, 邱健, 邢海平, 唐涛. 聚乙烯-g-聚苯乙烯对线性低密度聚乙烯/聚苯乙烯共混物机械性能和发泡行为的影响[J]. 应用化学, 2016, 33(7): 756-765.

ZHANG Guangchun, QIU Jian, XING Haiping, TANG Tao. Influence of Polyethylene-g-polystyrene on the Mechanical Properties and Foaming Behavior of Linear Low Density Polyethylene/Polystyrene Blends[J]. Chinese Journal of Applied Chemistry, 2016, 33(7): 756-765.

参考文献

[1]	JIAO Lei,CHEN Cong,CHEN Cheng,et al.Preparation and Characterization of Cross-Linked PVC/TPU Lightweight Materials[J]. Acta Polym Sin,2012,(5):513-520(in Chinese). 焦雷,陈聪,陈程,等. 交联型PVC/TPU轻质材料的制备和表征[J]. 高分子学报,2012,(5):513-520.
[2]	ZHONG Yalin,HUANG Hanxiong. Cellular Structure Manipulation of Microcellular PP/POE Blends Based on Phase Morphology[J]. Acta Polym Sin,2015,(6):720-726(in Chinese). 钟亚林,黄汉雄. 基于相形态的微孔发泡PP/POE共混物泡孔结构调控[J]. 高分子学报,2015,(6):720-726.
[3]	Gersappe D,Irvine D,Balazs A C,et al.The Use of Graft Copolymers to Bind Immiscible Blends[J]. Science,1994,265(5175):1072-1074.
[4]	MA Jingjing,HUANG Baotong. Study on the Use of Graft Copolymer EPR-g-PS as a Compatibilizer for PS/EPDM Blends[J]. Chinese J Appl Chem,1984,1(4):34-39(in Chinese). 马京晶,黄葆同. 接枝共聚物EPR-g-PS作PS/EPDM共混体系增容剂的探讨[J]. 应用化学,1984,1(4):34-39.
[5]	LIU Yanlong,KE Zhuo,YIN Ligang,et al.Combined Lewis Acids Catalysed in-Situ Compatibilization of Poly(octene-ethylene) and Polystyrene Blends[J]. Chinese J Appl Chem,2009,26(10):1129-1133(in Chinese). 刘焱龙,柯卓,尹立刚,等. 双路易斯酸催化原位增容乙烯辛烯共聚物/聚苯乙烯的共混物[J]. 应用化学,2009,26(10):1129-1133.
[6]	Machi S,Kamel I,Silverman J. Effect of Swelling on Radiation-induced Grafting of Styrene to Polyethylene[J]. J Polym Sci,Part A-1: Polym Chem,1970,8(11):3329-3337.
[7]	Rabie A,Odian G. Kinetics of Diffusion-Free Radiation Graft Polymerization of Styrene onto Polyethylene[J]. J Polym Sci:Polym Chem Ed,1977,15(2):469-488.
[8]	Kim S,Kim J K,Park C E. Effect of Molecular Architecture of in situ Reactive Compatibilizer on the Morphology and Interfacial Activity of an Immiscible Polyolefin/Polystyrene Blend[J]. Polymer,1997,38(8):1809-1815.
[9]	Sun Y J,Baker W E. Polyolefin/Polystyrene in situ Compatibilization Using Friedel-Crafts Alkylation[J]. J Appl Polym Sci,1997,65(7):1385-1393.
[10]	Díaz M F,Barbosa S E,Capiati N J. Reactive Compatibilization of PE/PS Blends. Effect of Copolymer Chain Length on Interfacial Adhesion and Mechanical Behavior[J]. Polymer,2007,48(4):1058-1065.
[11]	Shahbazi K, Razavi Aghjeh M K, Abbasi F, et al. Rheology, Morphology and Tensile Properties of Reactive Compatibilized Polyethylene/Polystyrene Blends via Friedel-Crafts Alkylation Reaction[J]. Polym Bull,2012,69(2):241-259.
[12]	Carrick W L. Reactions of Polyolefins with Strong Lewis Acids[J]. J Polym Sci,Part A-1:Polym Chem,1970,8(1):215-223.
[13]	Sun Y J, Willemse R J G, Liu T M, et al. In situ Compatibilization of Polyolefin and Polystyrene Using Friedel-Crafts Alkylation through Reactive Extrusion[J]. Polymer,1998,39(11):2201-2208.
[14]	Chung T C,Lu H L,Ding R D. Synthesis of Polyethylene-g-polystyrene and Polyethylene-g-poly(p-Methylstyrene) Graft Copolymers[J]. Macromolecules,1997,30(5):1272-1278.
[15]	Zhang G,Wang Y,Xing H,et al.Interplay Between the Composition of LLDPE/PS Blends and Their Compatibilization with Polyethylene-graft-polystyrene in the Foaming Behaviour[J]. RSC Adv,2015,5(34):27181-27189.
[16]	Wunderlich B,Macromolecular Physics[M]. 3rd Ed,Vol. 3. New York: Academic Press,1980:40.
[17]	Zhai W,Wang H,Yu J,et al.Foaming Behavior of Isotactic Polypropylene in Supercritical CO2 Influenced by Phase Morphology via Chain Grafting[J]. Polymer,2008,49(13/14):3146-3156.