Biodegradable polylactide/modified polycaprolactone (PLA/mPCL) blends were successfully prepared by sustainable electron-induced reactive processing (EIReP) without introducing any chemical compatibilizers. The effects of EIReP modification and mPCL content on the properties of PLA/mPCL blends were comprehensively examined and analyzed. The dynamic rheology test showed that the complex viscosity and storage modulus of the EIReP-modified PLA/mPCL blends increased significantly, implying an improved melt strength and elasticity. The PLA crystallization was effectively affected by EIReP treatment, as evidenced by the reduced cold crystallization peak and remarkably enhanced crystallinity of the PLA phase. The crystallinity of PLA increased from 2.4 to 18.0% after EIReP treatment, and it further rose to 38.4% by introducing 10 wt % mPCL. Moreover, the isothermal crystallization rate increased by adding mPCL contents, and the blend with 5 wt % mPCL showed the lowest half crystallization time. It was found that the PLA thermal resistance investigated by dynamic mechanical analysis was effectively enhanced with the characteristics of higher modulus compared with nonmodified blends. The Charpy impact test revealed that the impact toughness of the EIReP-treated blends improved, implying a superior interfacial adhesion and chain interaction between the two polymer phases.

No abstract

In this work, natural rubber (NR) was masticated using an internal mixer to fit the requirements of reactive blending with polylactide and characterized by size exclusion chromatography (SEC), Fourier-transform infrared (FT-IR) spectroscopy and dynamic rheology measurements. Subsequently, the effect of elevated temperatures (25 °C, 80 °C, and 170 °C) on the electron beam (EB) induced crosslinking and degradation of masticated natural rubber (mNR) in a nitrogen atmosphere without adding crosslinking agents has been investigated. The sol gel investigation showed that the gel dose of mNR slightly increased with increasing irradiation temperature, which is also confirmed by the swelling test. The chain scission to crosslinking ratio (Gs/Gx) was found to be less than 1 for irradiated mNR at 25 °C and 80 °C, suggesting a dominating crosslinking behavior of mNR. However, a significant increase of Gs/Gx ratio (~1.12) was observed for mNR irradiated at 170 °C due to the enhanced thermal degradation behavior at high temperature. A remarkably improved elasticity (higher complex viscosity, higher storage modulus, and longer relaxation time) for EB modified mNR was demonstrated by dynamic rheological analysis. Particularly, the samples modified at higher temperatures represented more pronounced elasticity behavior which resulted from the higher number of branches and/or the longer branched chains.

The authors prepared crosslinkable toughened polypropylene to be used for simultaneous spinning of hybrid yarn and the preparation of continuous glass fiber-reinforced polypropylene composites by filament winding to be consolidated by compression molding. A subsequent electron treatment aims on crosslinking of matrix as well as enhancement of interfacial adhesion in the interphase of glass fiberreinforced polypropylene composites. The authors evaluate the crosslinking behavior as well as the tensile properties of crosslinkable toughened polypropylene. Finally, the authors use transverse tensile test and single fiber pull-out test in order to study the effect of matrix modification and electron treatment on continuous glass fiber-reinforced polypropylene composites as well as on single glass fiber polypropylene model microcomposites.

EOC toughened PP with increased interfacial adhesion due to EOC–PP grafting was prepared by continuous EIReP and in continuation the rheological, morphological and mechanical properties of EOC toughened samples were investigated.