High strength insulating polymeric composite based on recycled/virgin polyethylene terephthalate (PET) reinforced with hydrous magnesium silicate (talc)

Abstract

In the current work, post-consumer polyethylene terephthalate (PET) bottles were reclaimed and reinforced with hydrous magnesium silicate, Mg3Si4O10(OH)2 commonly known as talc and with virgin PET (VPET) for the development of high strength polymeric composites. The composite sheets were prepared using the thermomechanical melt processing method followed by a thermal press technique. VPET was mixed during melt processing of recycled PET (RPET) in a specific ratio to suppress thermal degradation and hydrolysis of developed composite. Various blends of the composite samples of VPET and RPET (RPETx - VPET1-x) with a fixed ratio of talc were prepared and investigated for their strength, conductivity and micro-properties. 45 μm talc particle in ratio 1 to 4 was used. The effect of the talc addition on mechanical properties of the composites at the sub-micron scale was investigated through nanoindentation with quasi-continuous stiffness mode (QCSM) to analyze the nano-mechanical properties as a function of contact displacement. Surface morphology and composition were studied through scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX), which showed a uniform dispersion of talc particles with no agglomerates on the surface. Compressive strength was determined with the universal testing machine (UTM) that revealed the highest compressive strength of RPET80 – VPET20 blend with a lowest thermal conductivity gradient value of 0.0213 W.m−1 observed, thus making it preferable material for insulation purposes. Load-displacement curves displayed the harder behavior of the composite sheet containing RPET80 – VPET20/talc as it needed 100 μN load to impose a penetration depth of 7.5 μm only. The elastic modulus and hardness of RPET80–VPET20/talc composite was significantly improved as compared to other samples.

Keywords

• Recycled plastic
• Tensile strength
• Polymeric composite
• Polyethylene terephthalate (PET)
• Thermal conductivity
• Talc