Impact Strength Of High Density Polyethylene Research Articles

Development of Eco-Friendly Flame-Retarded High Density Polyethylene Composites

The use of ammonium polyphosphate (APP) and expanded graphite (EG) as a flame retardant for polymer generally requires a relatively high amount of addition to achieve a flame-retardant effect, and is liable to cause a decrease in strength of the material. Therefore, in this study waste diatomite was used as an eco-friendly flame-retardant for high density polyethylene (HDPE) to reduce the amount of APP and EG and can reach the flame-retardant level. Moreover, the waste diatomite was heat treatment and surface modified by silane coupling agent to improve its compatibility with HDPE. The results show that the tensile strength of the HDPE drops sharply after the addition of the APP and EG. However, replace some of the APP and EG by the modified diatomite can slow down the decline and maintain the basic physical properties of the material. The impact strength of HDPE was also decreased by the addition of APP, EG and untreated diatomite. However, the impact strength of HDPE was increased after adding the surface modified diatomite. It can be seen from the experimental results that the addition of the waste diatomite modified by the silane coupling agent can reduce the usage of the flame retardant such as APP and EG, and increase the strength by increasing the compatibility between the plastic and the inorganic material. Moreover, this eco-friendly formulation can reach the UL-94 HB level, and it can be applied to interior decoration or as building materials in the future. Thus, it can not only recycle the wastes, but also reduce the threat caused by fire.

Green composites based on high density polyethylene and recycled coffee gunny: Morphology, thermal, and mechanical properties

In this study, recycled coffee gunny (RCG) was used to reinforce high density polyethylene (HDPE). Maleic anhydride grafted polyethylene (MAPE) was added as a compatibilizer. Moreover, the RCG was chemically treated to enhance the compatibility between fiber and HDPE matrix. A series of RCG reinforced composites were prepared and the effects of MAPE and chemical modification of RCG on the mechanical and thermal properties of HDPE were investigated. The results of thermal and mechanical properties of composites revealed that the increments of heat deflection temperature, tensile strength, and impact strength of HDPE were 16[Formula: see text]C, 19.64% and 43.63% by the addition of modified coffee gunny, respectively. It reveals that the HDPE was reinforced with the coffee gunny, and thus can effectively reuse the discarded resources.

Compatibility study of high-density polyethylene with ethanol–gasoline and biodiesel

To further evaluate the compatibility of high-density polyethylene (HDPE) with the biofuels included ethanol–gasoline E30 and biodiesel B30, especially the change of mechanical properties of HDPE over soaking time, soaking tests were performed in E30 and B30 fuels at 45°C for 1608 h. Volume/mass change, yield stress, yield elongation, and impact strength of HDPE were measured at different soaking times. In all fuel soaking tests, more fuel absorption occurred between HDPE and fuels than oxidative damage. Due to higher polarity of bioethanol, E30 is less easily absorbed by HDPE than gasoline and causes less volume and mass change of HDPE. Compared with gasoline and E30, diesel and B30 were less likely to be absorbed by HDPE and there was no significant different of HDPE volume and mass change soaked in them. As fuel could be more easily stored in the amorphous phase of the HDPE than in the crystalline phase, the significant increase of yield elongation and little change of yield stress and the absorbed fuel may act as a plasticizer in HDPE. The increase of impact strength was due to the HDPE became more ductile after fuel soaking rather than strength increase. The compatibility research between HDPE and biofuel can help design engineers to evaluate the performance changes of plastic fuel tank products made of HDPE after long-term fuel soaking.

Physical Properties of Polyethylene Modified with Crude Palm Oil

The influence of small amount of crude palm oil (CPO) content on the physical properties of high density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) was investigated. The HDPE and LLDPE containing 2%, 3%, and 5% CPO were prepared in a twin-screw extruder. Then films of 0.2 mm thickness were produced by using blown film technique. The improvement in tensile strength and elongation at break with a concurrent decline in density implied the enhancement in toughness of the polymers by the addition of CPO. A gradual increase in impact strength of HDPE with the CPO content further supported the previous notation. The enhancement in the physical properties in the presence of CPO is believed to be attributed to the increased chain mobility of the polymer along with improved orientation strengthening in HDPE and LLDPE. Evidence from scanning electron micrographs was also used to support this contention. The decline in impact strength of LLDPE with the addition of CPO is associated with the formation of defects in the amorphous phase of LLDPE.

Impact strength of high-density polyethylene with various molecular weight distributions

The Charpy impact strength of high-density polyethylene specimens prepared under low pressure with average molecular weight from 60·103 to 1.5·106 and differing substantially in molecular weight distributions has been studied at room temperature and at −190°C. It is shown that, both at room temperature and at temperature considerably below the glass-formation temperature, the impact strength of polyethylene in the range of molecular weights mentioned is determined mainly by the content of fractions with molecular weights about 105 and more and does not depend on the width of the molecular weight distribution.