Thermal and mechanical characterization of composite materials from industrial plastic wastes and recycled nylon fibers for floor paving tiles application.

Industrial plastic waste is growing globally at an alarming rate and environmental pollution from traditional landfill disposal and incineration treatments are of great concern. As a strategy to reduce plastic pollution, value-added composite materials from industrial plastic wastes reinforced with recycled nylon fibers for use in floor paving tile applications were developed. This is to address the disadvantages of existing ceramic tiles which are relatively heavy, brittle, and expensive. The plastic waste composite structures were produced via compression molding technique at an optimized randomly oriented constant fiber volume fraction of 50 wt% after the initial sorting, cleaning, drying, pulverizing, and melt-mixing. The molding temperature, pressure, and time for the composite's structures were 220 ℃, 65 kg.cm-3, and 5 min respectively. The composites' thermal, mechanical, and microstructural properties were characterized in accordance with appropriate ASTM standards. From the results obtained, the differential scanning calorimetry (DSC) of mixed plastic wastes and nylon fiber wastes showed a processing temperature range of 130-180 ℃, and 250 ℃ respectively. Thermal degradation temperature (TGA) of the plastic and nylon fiber waste composites were stable above 400 ℃ with maximum bending strength, however, the reinforced plastic waste sandwiched composite structures had outstanding mechanical properties indicating unique characteristics suitable for floor paving tiles. Hence, the current research has developed tough and lightweight tiles composites that are economically viable, and their application will contribute to the development of the building and construction sectors thereby reducing about 10-15% of annual plastic waste generation and a sustainable environment.

Synergistic Effect of Partial Replacement of Carbon Black by Palm Kernel Shell Biochar in Carboxylated Nitrile Butadiene Rubber Composites.

With the rapid development of the palm oil-related industry, this has resulted in the high production of palm oil waste. The increasing amount of palm oil waste has become an alarming issue in which researchers have carried out studies that this palm oil waste has the potential to be used as a biomass source. Carbon black (CB) is the most preferred reinforcing filler in the rubber industry but it has a disadvantage where CB is carcinogenic and a petroleum-based product. Hence CB is less sustainable. Palm kernel shell (PKS) derived from palm oil waste can be turned into palm kernel shell biochar (PKSBc) which can potentially be a value-added, sustainable biofiller as reinforcement in rubber composites. In this study, PKSBc is hybridized with CB (N660) at different loading ratios to be filled in carboxylated nitrile butadiene rubber (XNBR). This study aims to elucidate the effect of the varying ratios of hybrid CB/PKSBc on the rheological properties, abrasion resistance, and hardness of XNBR composites. In this study, both CB and PKSBc are incorporated into XNBR and were then cured with sulphur. The composites were prepared by using a two-roll mill. Different compositions of hybrid CB/PKSBc were incorporated. The rheological properties and physicomechanical properties, such as abrasion resistance and hardness of the vulcanizates, were investigated. Based on the results, as the loading ratio of PKSBc in hybrid CB/PKSBc increases, the cure time decreases, and the cure rate index increases. The abrasion resistance and hardness values of vulcanizates were maintained by the high loading of PKSBc which was due to the porous structure of PKSBc as shown in the morphological analysis of PKSBc. The pores of PKSBc provided mechanical interlocking to reduce volume loss and maintain the hardness of vulcanizates when subjected to force. With this, PKSBc is proven to be a semi-reinforcing filler that could not only act as a co-filler to existing commercialized CB, but PKSBc could also fully substitute CB as reinforcement in rubber, specifically XNBR as it is able to provide high abrasion resistance and hardness to the rubber composites. This would mean the performance of PKSBc is comparable with CB (N660) when it comes to maintaining the physicomechanical properties of XNBR composites in terms of abrasion resistance and hardness. Therefore, this approach of using eco-friendly filler derived from palm oil agricultural waste (PKSBc) can reduce the abundance of palm oil waste, be a sustainable alternative to act as a co-filler in hybrid CB/PKSBc to decrease the usage of CB, and helps to enhance the quality of existing rubber-based products.