The two macromolecular antioxidants, P(3,5-di-tert-butyl-4-hydroxy cinnamic acid-alt-N-phenylmaleimide) (PCN) and P(3-butene-1-yl-3,5-ditert-butyl À4-hydroxyphenyl propionate-alt-N-phenylmaleimide) (PPN) were designed and synthesized via free radical copolymerization. The structures of the resulting PCN and PPN antioxidants were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy ( 1 H NMR), and gel permeation chromatography. In addition, the effect of the two macromolecular antioxidants on the thermal oxidation aging resistance of polyamide 6 (PA6) was studied. According to the analysis of differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, dynamic viscosity, and the mechanical property of PA6 and its blends, these two types of macromolecular antioxidants protected the molecular chain of PA6 from breaking, protected the crystallization of PA6 and maintained the stability of PA6 crystal form, improved the activation energy of thermal degradation and thermal stability of PA6, enhanced the strength and elasticity of PA6 and maintained the mechanical properties of PA6 during aging to a certain extent.

Pyrophyllite (Prl), an aluminosilicate with a balanced mineral structure and extremely small particle size, appears to be an ideal filler but is rarely used in polymers. Herein, a method for the application of pyrophyllite in polymers is reported. A multifunctional filler is prepared by epoxy-modified pyrophyllite and incorporated into poly(latic acid) (PLA) to enhance its processability and crystallization properties. Results show the effectiveness of epoxy-modified Prl in composite film with a significant reduction in glass transition temperature, and noteworthy increment in crystallinity and spherulite growth rate. Water vapor barrier properties of PLA composite films increase over 30% with a range of Prl Loading. Furthermore, an enhancement of the tensile strength is increased by 30% and strain at break by 337.1% for PLA composite films compared to neat PLA. This work provides a new idea to prepare the functionalized pyrophyllite fillers and a theoretical basis to develop the application of pyrophyllite for polymers.

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