Accelerated weathering performance of injection moulded PP and LDPE composites reinforced with calcium rich waste resources

This study aims to assess and understand the accelerated weathering performance of injection moulded PP and LDPE composites reinforced with calcium rich waste resources for the first time. Two different calcium rich wastes: FGD gypsum and marble waste are incorporated without any chemical treatment in the polymer matrices. Visual appearance, chemical changes, flexural properties (strength, modulus and elongation) and surface morphology are analysed. Weathered surfaces are studied to analyse the structural changes with morphology by FTIR and SEM. LDPE showed higher visual stability by weathering with enhanced flexural properties for FGD gypsum composites. FTIR analysis revealed that the composites prepared with LDPE had a stabilizing effect on photo-degradation (minimum carbonyl index=1.09-1.14), which correlates well with the results of mechanical testing, showing these composites retained remarkable mechanical properties (retention rate>85%.) after weathering. Visual appearances, physical and mechanical properties of polymer composites are affected by the accelerated weathering condition. UV radiation in combination with temperature, humidity and water spray leads to polymer crystallinity with degradation resulting in weaker interfacial bonding and detachment of filler from matrix. Results show that the flexural strength of weathered FGD gypsum-PP, marble waste-PP and marble waste-LDPE composites decreased about 7-38%, 50-59% and 5-6%, respectively. Flexural strength of the weathered FGD gypsum-LDPE composites increased about 7-12%. The present study implies that both the reinforcements can enhance the properties of PP and LDPE composites after accelerated UV weathering exposure with potential for civil engineering applications. FGD gypsum is more prominent while structural and durability performances are taken into account. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study evaluates the accelerated weathering performance of injection moulded PP and LDPE composites reinforced with calcium rich waste resources. The results show that LDPE composites exhibit better visual stability and enhanced flexural properties after weathering. Accelerated weathering conditions significantly affect the visual appearance, physical and mechanical properties of the polymer composites.