Yes / Recycling of polymers is a necessity in our intensively consuming polymer world but the nature of polymers is such that they are prone to thermal degradation when re-extruded and this poses technical challenges to recycling. This article describes research that seeks to rebuild the structure of degraded PA6. We present data from controlled experiments with pristine pPA6 extruded to form a base recycle rPA6 to which we added two chain extenders, separately: one with anhydride multifunctionality (ANHY), highly reactive with amide groups and one with epoxy multifunctionality (EPOX), less reactive. We found from rheological data carried out in the linear viscoelastic region (so as to study structural changes) a striking difference in the ability of the chain extenders to rebuild structure: 306% increase in the complex viscosity of rPA6/ANHY compared to 25% in that of rPA6/EPOX of the base rPA6. Mechanical and thermal (DSC and TGA) tests confirmed the superior efficacy of the multifunctional anhydride chain extender. Beside the practical benefit that ensues from this research, it also provides a strategic platform to develop chain extenders for other degrading polymers on the basis of understanding the degradation chemical reaction and targeting the most reactive end group of the split chains.

Thermoplastic Vulcanizates (TPVs) are itself a commercially high valued group of polymer blend. They render technological properties of conventional vulcanized elastomers with the ease of thermoplastic melt (re)processability. With ever growing market, TPVs have got plenty of applications among various fields. Here, the technological properties of these TPVs were tailored according to the purpose by interplaying physical parameters of polymers and advanced high energy electron technology. Electron irradiation, though a well-known technique for cross-linking in polymer industry, is only restricted to final product treatment. We take it to the next level by coupling a conventional internal mixer and a high energy electron accelerator. Polypropylene (PP) and natural rubber (NR) based TPVs have been prepared using this new reactive processing technology, named Electron Induced Reactive Processing (EIReP). Various electron treatment parameters were explored to maximize technological properties of TPVs. Effects of various polyfunctional monomers (PFM) were also studied. In an endeavor to develop a potential method for customization, deep insights of macroscopic and microscopic structure of these TPVs were presented with the help of various advanced scientific characterization techniques. Commonly faced difficulties like viscosity mismatch, cure rate mismatch, and incompatibility due to different molecular structures were furnished along with plausible solutions. Investigation of phase inversion from co-continuous matrix to thermoplastic matrix was dealt with special care as it helps to understand structure property correlation for all TPVs. To make the whole effort relevant, at the end of this thesis a summary of various technological properties has been given for the newly processed and commercially available TPVs.

Thermoplastic Vulcanizates (TPVs) are itself a commercially high valued group of polymer blend. They render technological properties of conventional vulcanized elastomers with the ease of thermoplastic melt (re)processability. With ever growing market, TPVs have got plenty of applications among various fields. Here, the technological properties of these TPVs were tailored according to the purpose by interplaying physical parameters of polymers and advanced high energy electron technology. Electron irradiation, though a well-known technique for cross-linking in polymer industry, is only restricted to final product treatment. We take it to the next level by coupling a conventional internal mixer and a high energy electron accelerator. Polypropylene (PP) and natural rubber (NR) based TPVs have been prepared using this new reactive processing technology, named Electron Induced Reactive Processing (EIReP). Various electron treatment parameters were explored to maximize technological properties of TPVs. Effects of various polyfunctional monomers (PFM) were also studied. In an endeavor to develop a potential method for customization, deep insights of macroscopic and microscopic structure of these TPVs were presented with the help of various advanced scientific characterization techniques. Commonly faced difficulties like viscosity mismatch, cure rate mismatch, and incompatibility due to different molecular structures were furnished along with plausible solutions. Investigation of phase inversion from co-continuous matrix to thermoplastic matrix was dealt with special care as it helps to understand structure property correlation for all TPVs. To make the whole effort relevant, at the end of this thesis a summary of various technological properties has been given for the newly processed and commercially available TPVs.

In present study, high energy electrons were used to modify blends based on RP and PP under two conditions: stationary and in-stationary conditions. Modification of blend under stationary condition is a process which is established in industrial application and where required absorbed dose is applied to form parts (after molding) at room temperature and in solid state. On the contrary, the modification of blend with high energy electrons under in-stationary condition is a new process (electron induced reactive processing) where required absorbed dose is applied to a molten state during melt mixing process. The modification of blend based on RP and PP under stationary condition resulted in slightly enhancement of tensile properties while the modification of this blend under in-stationary condition resulted in deterioration of tensile properties due to degradation of the PP matrix. Thus, special grafting agent (GA) is required for improving the tensile properties. The effect of different GAs on tensile, thermal, dynamic mechanical as well as morphological properties and melt flow properties of blends based on RP and PP were determined. The optimum absorbed dose for modification of blend based on RP and PP under both conditions was evaluated. In addition, the effect of treatment parameters of electron induced reactive processing was investigated.

In present study, high energy electrons were used to modify blends based on RP and PP under two conditions: stationary and in-stationary conditions. Modification of blend under stationary condition is a process which is established in industrial application and where required absorbed dose is applied to form parts (after molding) at room temperature and in solid state. On the contrary, the modification of blend with high energy electrons under in-stationary condition is a new process (electron induced reactive processing) where required absorbed dose is applied to a molten state during melt mixing process. The modification of blend based on RP and PP under stationary condition resulted in slightly enhancement of tensile properties while the modification of this blend under in-stationary condition resulted in deterioration of tensile properties due to degradation of the PP matrix. Thus, special grafting agent (GA) is required for improving the tensile properties. The effect of different GAs on tensile, thermal, dynamic mechanical as well as morphological properties and melt flow properties of blends based on RP and PP were determined. The optimum absorbed dose for modification of blend based on RP and PP under both conditions was evaluated. In addition, the effect of treatment parameters of electron induced reactive processing was investigated.