Papers by Keyword: Reprocessing

Abstract: The utilization of recycled materials in the production of plastic products is an environmentally conscious and economically viable approach. This study delves into the mechanical and flow properties of low-density polyethylene (LDPE) blends, comparing virgin low-density polyethylene (vLDPE), recycled low-density polyethylene (rLDPE) and vLDPE/rLDPE blends with different ratio (100/0, 75/25, 50/50, 25/75, 0/100) for the purpose of reprocess into variable high-quality end products with minimal modification. Mechanical properties, such as tensile strength, elongation at break, Young’s modulus, flexural strength, and flexural modulus, were examined to assess the suitability of rLDPE in comparison to its virgin counterpart. Our results demonstrate that vLDPE/rLDPE blend exhibits mechanical properties comparable to those of vLDPE, suggesting its potential as a sustainable alternative for reprocessing. Flow properties, specifically melt flow index (MFI), were also assessed to evaluate the processability of the LDPE blends. The findings reveal that the flow properties of LDPE blends are within an acceptable range for extrusion moulding, indicating that these materials can be effectively processed without major adjustments to manufacturing processes. This research underscores the feasibility of incorporating rLDPE into vLDPE for reprocessing into variable products, offering both economic and environmental advantages. By extending the lifecycle of LDPE materials through recycling, we can contribute to reducing waste and the overall environmental footprint while maintaining the desired mechanical and flow properties for high-quality end products.

Abstract: Reprocessable and recyclable self-healing rubber composites were fabricated by mixing natural rubber (NR) with carbon black (CB) filler in the presence of zinc thiolate (ZT) to form the ionic association in the rubber system. This work investigated and compared the unfilled and natural rubber filled with 5phr of carbon black. The recycling process was repeated three times, and the mechanical performance was measured each time. Tensile strength was increased by more than 430% for unfilled rubber and 520% for NR/5CB composites after the third recycling process. Tear strength was also increased with the number of the recycling process. According to a welding test ability, the developed materials showed potential for repair. Scanning electron micrographs revealed that as the recycling number increased, the white spot of ZT responsible for generating the ionic network reduced as more ZT was converted into Zn²⁺ salt bonding.

Abstract: Polypropylene filled calcium carbonate (CaCO₃) nanocomposites were fabricated by employing melt blending/compounding method using masterbatch. To investigate the efffect of reprocessing on the melting properties of PP/CaCO₃ nanocomposites, the melt compounding process was conducted twice (two cycles). The effect of nano-CaCO₃ loadings (i.e. 5, 10 and 15 wt%) on the melting properties of PP/CaCO₃ nanocomposites were also studied. The meling properties of the nanocomposites were analyzed by using a DSC (Differential Scanning Calorimetry). Additionally, the nanocomposites samples were also analyzed by an SEM (Scanning Electron Microscopy). The SEM analysis results revealed that at higher nano-CaCO₃ loading (i.e. 15 wt%), the nano-CaCO₃ particles in the 2^nd cycle were more well distributed/dispersed in the polypropylene matrix as compared to the 1^st cycle. Whereas, the DSC test results showed that the crystallinity of the nanocomposites samples were similar to that of neat PP for the 1st cycle of melt blending process, which was about 41%. In the other hand, for the 2^nd cycle, the crystallinity of the samples slightly increased wtih increasing nano-CaCO₃ loadings, which were about 39.6; 43; 44% for nano-CaCO₃ loadings of 0, 5, 10 wt%, respectively. Nevertheless, at the highest nano-CaCO₃ loadings (i.e. 15 wt%), the crystallinity of the nanocomposites (i.e. NCC-15-II) decreased again and lower than that of neat PP, which was about 37.7%.

Abstract: Concern for the environment, both in terms of limiting the use of finite resources and the need to manage waste disposal, has led to increasing pressure to recycle materials at the end of their useful life. This work describes the effects of reprocessing on the mechanical properties of oil palm fiber reinforced polypropylene composites (PFC). Composites, containing 30wt% fiber with 3wt% Maleate Polypropylene as a coupling agent, were reprocessed up to six times. For this composite, tensile strength (TS) and Young modulus (YM) were found to decrease by 9.6% and 4.7% after being reprocessed for six times. Flexural strength was found to decrease by 23.8% with increased number of reprocessing. The hardness numbers of the composite were found to increase by 7.43% from 72.10 to 77.89 after the sixth reprocessing. In general the degradation on the mechanical properties is considered to be small and PFC has potential to be reprocessed.

Abstract: In this study, low density polyethylene (LDPE) matrix composites were manufactured with the ratios of 20%, 30% and 40%wt hazelnut and peanut reinforcements as the natural fibers. Composite plates were manufactured by using a single screw extruder. Various tests and measurements are performed to obtain mechanical properties such as density, tensile strength (TS), Youngs modulus (YM), failure strain (FS), impact strength (IS) etc. as well as the effect of maleic anhydride grafted resin as an additive with different ratios was investigated and the optimum composite content was obtained. This preliminary work showed that hazelnut and peanut fillers could be utilized with proper additives in order to produce the composite materials with good physical and mechanical properties.

Abstract: Acrylonitrile-Butadiene-Styrene (ABS)/CaCO₃ composites were reprocessed under normal conditions. The effects of reprocessing on the degradation of ABS were investigated by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The mechanical properties of the reprocessed materials were measured. In this paper, a method to evaluate the degradation of ABS in ABS/CaCO₃ composites by FTIR was described. The results show that within the range of the reprocessing cycles studied, as the number of reprocessing cycles increased, the impact strength of composite was significantly reduced if the content of CaCO₃ is lower than 10%, due to the degradation of rubber phase. However, the impact strength was almost unchanged when the content of CaCO₃ was higher than 15%.