Synthesis And Application Of The Atactic Poly(1-butene) And Block Copolymer

In this work, linear and star-shaped atactic poly (1-butene) and polyethylene-poly (1-butene) block copolymer (PE-b-P-1-Bt)were sythesised by combination of anionic polymerization techniques and hydrogenation with nickel. The molecule structure parameter and thermal performance of the samples obtained are characterized by FT-IR, GPC, X-ray Diffraction, DSC,'H-NMR and 13C-NMR. Major work and conclusions are as follows:1. Linear-shaped polybutadiene with almost 100%1,2-structure and stereoblock polybutadiene with different block ratios were obtained by changing the quantity and adding time of DPE with single lithium initiator in the polymerization process. Linear-shaped atactic poly(1-butene) (at-P-1-Bt) and polyethylene-poly(1-buene) block copolymer (PE-b-P-1-Bt) were sythesised with 100% hydrogenation by increasing the content of catalyst and prolonging the reaction time. The glass transition temperature (Tg) of linear-shaped atactic poly(1-butene) was-25.4℃～22.7℃. The WAXD analysis of the poly(1-butene) exhibited no sharp diffraction peak reflecting crystal. These polymers obtained are atactic and amorphous. The heating curves of linear-shaped PE-b-P-1-Bt appeared the Tg of P-1-Bt block at the low temperature region and the melting endothermic peak of PE block at the high temperature region. The melting temperature (Tm) and crystallinity almost remained nearly unchanged and Tg increases slightly with adding the content of polyethylene block.2. Star-shaped 1,2-polybutadiene and stereoblock polybutadiene with different block ratios were obtained with multi-lithium initiator. Meanwhile, the effect of DVB dosage, DPE dosage and single-arm molecular weight on the molecular weight of star polymer were investigated comprehensively. The results showed that for star-shaped 1,2-polybutadiene, high molecular weight section content, molecular weight distribution and average arm number of the products increased with the content of DVB and DPE increasing. The single-arm molecular weight hardly change molecular weight distribution and average arm number of the products. For star-shaped structure block polybutadiene, high molecular weight section content, molecular weight distribution and average arm number of the products increased with the content of DVB increasing. The adding time of DPE determined the content of LvB block. The weight average molecular weight and distribution and average arm number decreased with the adding time delay of DPE. The Tg of star-shaped atactic poly(1-butene) was higher than line structure and increased with the rise of average arm number. In the DSC curve of star-shaped PE-b-P-1-Bt, the Tm and initial crystallization temperature remained nearly unchanged and the glass transition temperature of P-1-Bt block decreased with adding the content of polyethylene block.3. The atactic poly(1-butene) was used to toughen polypropylene. The effect of content and structure on the mechanical properties of blends were investigated. The results indicated that the mechanical properties of blends were improved with the content of at-P-1-Bt increasing.The elongation at break increased from 19.7% to 748%. At the same content of at-P-1-Bt, for linear-shaped structure the tensile strength and impact strength of blend increased with molecular weight rising, while elongation at break decreased. Star-shaped at-P-1-Bt had higher tensile strength and impact strength than linear-shaped.4. PE-b-P-1-Bt was used as compatibilizer to PP/LLDPE=80/20 blends. The effect of content and structure on the mechanical properties of blends were investigated. The results indicated that the elongation at break and impact strength increased significantly with increasing the content of compatibilizer. The polarizing microscopy and DSC results showed that PE-b-P-1-Bt on the PP/LLDPE blends exhibited a good compatibilization effect. In the blend of PP/LLDPE=80/20, the compatibilizer with low PE block content had better compatibilization effect and more excellent mechanical properties.