摘要
以活性负离子聚合法合成的不同分子量和单体配比的苯乙烯-异戊二烯-丁二烯三元共聚物橡胶(SIBR)为增韧剂,以双官能团引发剂引发,采用本体聚合方法合成了系列ABS树脂,利用经典相分离技术、SEC、TEM和力学试验对聚合试样的结构、分子量、形态及性能进行了表征,并以SEM对冲击后的断面形貌进行观察以探究其断裂机理.结果发现,随着SIBR分子量的增大,橡胶相尺寸增大,接枝率下降,相界面明显,但冲击强度有所提高;SIBR中St组分含量增加,粒子均匀,但刚性增大,对抗冲击性能不利.高Mn、低St组分含量SIBR抵抗裂纹形成和扩展的能力强,ABS呈韧性断裂方式,以丰富的银纹化、明显的剪切屈服和大量系联带的撕裂为主要断裂机理;低Mn、高St组分含量SIBR抵抗裂纹形成和扩展的能力较低,ABS以半韧性方式断裂,断裂机理以基体塑化、剥离和界面的应力白化现象为主.
The styrene-isoprene-butadiene terpolymer rubbers （SIBRs） with different molecular weights and monomer ratios were first synthesized by living anionic polymerization method. A series of ABS resins were prepared via bulk polymerization method under the initiation of difunctional initiator modified by the foresaid SIBR tougheners. The molecular structure,morphology and performances of ABS were characterized by typical phase-separating method, SEC, TEM and mechanical testing, respectively. And SEM technique was used for observing the fractured surfaces of specimens after impact in order to study the fracture mechanism. The results show that with increasing the molecular weight of SIBR,the rubber phase size increases and the grafting degree decreases besides gradually obvious phase interface and improved impact properties. Moreover, increasing the styrene content in SIBR could lead to relatively uniform particles,but goes against the impact resistance due to its rigidity. The SIBR with higher molecular weight and lower styrene content restrains the generation and development of cracks to a certain extent, and correspondingly,the ABS displays ductile fracture mode and the fracture mechanisms are mainly abundant crazing,obvious shear yielding and a great many ruptured ligaments. While the SIBR with lower molecular weight and higher styrene content could not efficiently resist the formation and expansion of cracks, ABS is fractured in quasi-ductile modes and matrix plasticization, stripping and stress whitening are the main fracture mechanism.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2012年第4期433-439,共7页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号20774015)
国家高技术研究发展计划(863计划
项目号2007AA03Z532)资助项目
关键词
ABS树脂
SIBR橡胶
结构
力学性能
断裂机理
ABS resin, SIBR rubber, Structure, Mechanical performance, Fracture mechanism
