Investigation of Fracture Stress in Deproteinized Natural Rubber with Poly(trimethylene carbonate) Grafted Microcrystalline Cellulose for Improved Dispersibility

The present work aimed to develop a novel deproteinized natural rubber (DPNR) composite reinforced with microcrystalline cellulose grafted with poly-(trimethylene carbonate) (MCC-<i>g</i>-PTMC). The hypothesis is that the amorphous and flexible PTMC chains improve the compatibility between MCC and DPNR, thereby enhancing mechanical properties. To verify this, MCC-<i>g</i>-PTMC was synthesized by ring-opening polymerization of trimehtylene carbonate and then blended with DPNR to evaluate its dispersibility and mechanical reinforcement. In the vulcanized DPNR/MCC-<i>g</i>-PTMC1, which introduced MCC/DPNR (28/72, w/w), the rubber exhibited stable mechanical properties compared to the conventional DPNR/MCC composite and the DPNR/MCC-<i>g</i>-PLLA composite grafted with the crystalline biodegradable polymer poly-(l,l-lactide) (PLLA). Specifically, the strain of DPNR/MCC-<i>g</i>-PTMC1 increased to 800%, while it was 750% the control samples of MCC/DPNR and DPNR/MCC-<i>g</i>-PLLA. The improvement of the stress at break maintain about 24 MPa, although it was around 22 MPa in the case of DPNR.