علوم و تکنولوژی پلیمر (Dec 2009)
Crystallization Behavior of PA6 in ABS/PA6 Blends Prepared by In Situ Polymerization and Compatibilization Method
Abstract
A new method was used to prepare ABS/PA6 blends by in situ polymerization and compatibilization method. In this process, ε-caprolactam monomer was polymerized in presence of ABS via activated anionic polymerization to produce PA6. The main ingredients of the reaction mixture included: monomer ()ε-caprolactam), catalyst Na-caprolactamate), microactivator HDI)( and macro-activator SMA)(. Then, in different steps caprolactam/ABS composition, micro-activator and macro-activator concentrations were selected as the variables. ABS/PA6 blends were prepared in an internal mixer at 200°C)( at three levels of ABS/caprolactam compositions ()25/75, 50/50, 75/25)(, with varied concentrations of HDI 4 and 6 phc)( and macro-activator 0, 3 and 6 phc)(. As a result of all the variations the blends produced different morphologies.In samples with dispersed structure, the particle size reduced with higher macro-activator content. Also, the effect of macro-activator at lower level of HDI was more significant, probably due to the competition between the activators in the reaction. In some of the blends, dispersed particles with sizes under 100 nm were observed. The crystalline structure of PA6 phase was investigated using XRD and DSC tests, which also showed changes with regard to initial compositionand activator contents. In pure samples only α-structure was detected, while in the blends of higher ABS content, γ-form appeared and at the ABS content of 75% only γ-form was observed. The crystallinity decreased as the function of ABS content. Pure synthesized PA6 showed higher Tm and Hc than the blends. The percentage crystallinity of the samples obtained from XRD and DSC tests showed good correlation
Keywords
