双螺杆挤出机转速比对胶粉及其天然橡胶并用胶性能的影响

Influence of screw speed ratios of twin screw extruder on properties of rubber powder and its natural rubber blends

用双螺杆挤出机对硫化胶粉进行机械力化学改性,得到改性胶粉(MWRP),将其与天然橡胶(NR)并用,研究了挤出机转速比对MWRP自由基浓度、交联密度以及MWRP/NR并用胶力学性能、微观形貌的影响。结果表明,随着转速比的降低,剪切作用增强,胶粉体系的交联网络结构得到破坏,体系自由基浓度呈现先上升后降低的趋势,胶粉的交联密度降低;MWRP/NR并用胶的力学性能得到改善,在转速比为3.5时,拉伸强度和扯断伸长率达到最大,分别为19.7 MPa和607%;并用胶拉伸断面的缺陷减少,胶粉颗粒与橡胶基体的相容性得到改善。

The modified rubber powder（ MWRP）was acquired via mechanochemical modification of vulcanized rubber powder by twin screw extruder,and then blended with natural rubber（ NR）. The influences of screw speed ratios of twin screw extruder on radical concentration, crosslinking density of MWRP as well as the mechanical properties,micromorphology of MWRP / NR blends were studied. The results showed that with the increase of screw speed ratio,the shearing strengthened, the crosslinking network structure of rubber powder system was damaged,and the radical concentration increased first and then decreased; the mechanical properties of MWRP / NR blends were improved, the tensile strength and elongation at break reached maximum 19. 7 MPa and 607% respectively when screw speed ratio was 3. 5; the defection of stretching surface of the blends decreased,so that the compatibility of rubber powder and rubber matrix improved.