This work was intended to provide an understanding of the effect of microcrystalline cellulose (MCC) on the mechanical properties of low-density polyethylene (LDPE). The impact resistance and the tensile properties of low-density LDPE/MCC composites were investigated. The weight fraction of MCC was varied at (0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt%). The obtained blends were then used to prepare the required tensile and impact testing samples by hot compression molding technique. It has been found that MCC has a strong influence on the mechanical properties of LDPE. At a low MCC weight fraction, there was a little improvement in the ultimate strength, fracture stress, and elongation at break, but at a high MCC weight fraction, the tensile properties were deteriorated and reduced significantly. The addition of 1 wt% MCC to LDPE enhanced the mentioned properties by 10, 25, and 6%, respectively. While at 30 wt% MCC, these properties were lowered by 36, 25, and 96%. The elastic modulus of LDPE composites was improved on all MCC weight fractions used in the study, at 20 wt% MCC, an increase in the elastic modulus by 12 folds was achieved. On the other hand and compared with the impact strength of pure LDPE, the addition of MCC particles enhanced the impact strength, the highest value obtained was for LDPE composites filled with 10 wt% MCC where the impact strength enhanced by two folds.

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°C to 103.5°C and decreased the melting temperature from 117°C to 113.6°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.