低相对分子质量反式聚丁二烯的合成及表征

Synthesis and characterization of low relative molecular mass trans-1,4-polybutadiene

采用负载钛催化体系溶液淤浆聚合法,以氢气为相对分子质量调节剂,合成了低相对分子质量的反式-1,4-聚丁二烯(LMTPB),通过IR,DSC表征了其结构及结晶状态。结果表明,随着氢气压力升高,LMTPB的相对分子质量降低;当氢气分压超过3MPa时,聚合物的特性黏数降至0.5dL/g,相对分子质量在2000以下。随氢气压力提高,反式-1,4-结构摩尔分数下降,但仍保持在86%以上,结晶度和熔点降低,溶解性提高。LMTPB是由相对分子质量大小和微观结构不同,结晶类型、结晶度和熔点不同的级分组成的混合物。

The polymerization of butadiene with adding hydrogen in presence of supported titanium catalyst was studied to synthesize low relative molecular mass trans-1,4-polybutadiene (LMTPB). Structure of the LMTPB was characterized with IR and DSC. With the increase of hydrongen pressure ,the relative molecular mass of the LMTPB decreased sharply. When hydrongen pressure was over 3 MPa, of the LMTPB decreased to under 0.5 dL/g, and its relative molecular mass was under 2 000. With hydrogen pressure increasing, the mole fraction of trans-1,4-unit and the Tm and the crystallinity of the LMTPB decreased also, but the solubility increases. LMTPB was made up of some fractions with different relative molecular mass and structure of trans-1,4-unit and melting point and crystallinity.