Thermal properties and degradability of low density polyethylene microcrystalline cellulose composites

The effect of microcrystalline cellulose (MCC) on the thermal properties (melting and crystallization temperatures and percentage crystallinity) and degradation of low density polyethylene (LDPE)-MCC blends were investigated. Weight percentages of MCC were varied at 0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt%. The thermal properties of the composites were studied using differential scanning calorimetry while the degradation test was carried out using soil burial method; the weight loss of LDPE/MCC composites was measured and analyzed over a period of 120 days. It has been found that the addition of MCC to LDPE increased the crystallization temperature from 99 degrees C to 103.5 degrees C and decreased the melting temperature from 117 degrees C to 113.6 degrees C. A rule of a nucleating agent has been given as an interpretation to this increase in the crystallization temperature and intensity of crystals by the increase of MCC content. The dramatic reduction was in the percentage crystallinity where the value reduced from 58% for neat LDPE to about 11% for LDPE/30 wt% MCC. On the other hand, the addition of MCC has a little effect on degradation of LDPE; the weight loss did not exceed 1.5% over a period of 120 days. It seems that even at high MCC concentration, LDPE long carbon chains restrict and increase the resistance to microorganism attack and hence, reduce the hydrolysis and degradability.