ENVIRONMENTAL PROPERTIES OF ENVIRONMENTALLY FRIENDLY CONSTRUCTION MATERIALS: RECYCLED LDPE COMPOSITES FILLED BY BLAST FURNACE DUST

ABSTRACT This study focused on creating a sustainable composite material using blast furnace dust of the iron-steel industry and plastic wastes of the plastic industry in order to reduce the embodied energy of the material and generate more sustainable material. In this study, varying amounts of blast furnace dust (BFD), which is the primary iron-steel industry waste and which is used as filler for recycled low-density polyethylene (LDPE), was mixed to create the composite material. The embodied energy, emissions to water and air (volatile organic compounds) of BFD filled LDPE composites were determined. It was found that the composite materials had less embodied energy compared with polymer-based flooring materials such as epoxy, polyurethane (PU) and polyvinylchloride (PVC). In addition, it was determined that the composite material did not release emissions to water and have fewer total volatile organic compounds (TVOCs). These results showed that the produced composite material could be used in buildings as a sustainable floor coating material, thus saving raw materials and supporting indoor air quality and recycling.

Preparation and Evaluation of Biodegradation Performance of Potato Starch Mixed LDPE Polymer Composites

The potential of biodegradable polymers has long been appreciated. In this work, an attempt has been made to synthesize biodegradable polymer composite from potato starch and low density polyethylene (LDPE) with different ratios of starch (0%-15% w/w) by using an extruder. The structure and morphology of film surfaces was studied using X-ray diffraction and scanning electron microscopy (SEM) respectively. The physical (density, water absorption), mechanical (tensile, flexural) and thermal (TGA and DTA) analyses of starch/LDPE bio-composites were evaluated through standard methods and instruments. Biodegradation tendency was investigated utilizing soil burial and Rockwell micro-hardness test.The results revealed that the density and water absorption of polymer blends increased with increasing the starch content in starch/LDPE composites. The tensile strength and elongation at break decreased with starch content whereas the elastic modulus, flexural strength and flexural modulus rose. The biodegradability of composites enhanced by increasing the starch content and the result was backed by weight loss during burial of the samples in soil for 90 days. Microhardness test also supported the biodegradation probability as hardness found to reduce extensively after soil burial. However, further study to decide the optimum starch loading alongwith some modifications to starch and LDPE is highly suggested to have a biodegradable LDPE polymer composite in a realistic time frame.

Enhanced Thermal Conductivity and Dielectric Properties of h-BN/LDPE Composites

Low-density polyethylene (LDPE), as an excellent dielectric insulating material, is widely used in electrical equipment insulation, whereas its low thermal conductivity limits its further development and application. Hexagonal boron nitride (h-BN) filler was introduced into LDPE to tailor the properties of LDPE to make it more suitable for high-voltage direct current (HVDC) cable insulation application. We employed melt blending to prepare h-BN/LDPE thermally conductive composite insulation materials with different contents. We focused on investigating the micromorphology and structure, thermal properties, and electrical properties of h-BN/LDPE composites, and explained the space charge characteristics. The scanning electron microscope (SEM) results indicate that the h-BN filler has good dispersibility in the LDPE at a low loading (less than 3 phr (3 g of micron h-BN particles filled in 100g of LDPE)), as well as no heterogeneous phase formation. The results of thermal conductivity analysis show that the introduction of h-BN filler can significantly improve the thermal conductivity of composites. The thermal conductivity of the composite samples with 10 phr h-BN particles is as high as 0.51 W/(m·K), which is 57% higher than that of pure LDPE. The electrical performance illustrates that h-BN filler doping can significantly inhibit space charge injection and reduce space charge accumulation in LDPE. The interface effect between h-BN and the substrate reduces the carrier mobility, thereby suppressing the injection of charges of the same polarity and increasing the direct-current (DC) breakdown strength. h-BN/LDPE composite doped with 3 phr h-BN particles has excellent space charge suppression effect and high DC breakdown strength, which is 14.3% higher than that of pure LDPE.