Strong, self-healing and flame-retardant elastomer composite based on epoxidized natural rubber, polylactic acid, chitosan and guanidine phosphate

With the rapid development of society, polymer materials are widely used in automotive, construction, and electronic components due to their excellent properties such as easy processing, cheap price, and corrosion resistance. However, most polymers, such as rubber and leather, suffer from poor mechanical properties, susceptibility to micro cracking and flammability. In this paper, an epoxidized natural rubber (ENR)/polylactic acid (PLA)/chitosan (CS)/guanidine phosphate (GP) composites with certain self-healing and flame-retardant properties are successfully prepared. The network structure is constructed by forming thermoplastic elastomers (TVPs) through ENR and PLA, and the amino groups on CS and GP can form hydrogen bonds with ENR, which improves the mechanical properties of ENR/PLA composites and gives the ENR/PLA/CS/GP composites excellent self-healing properties. Meanwhile, CS and GP can also form intumescent flame retardants to improve the flame-retardant properties of ENR/PLA composites. The results show that the mechanical strength of ENR/ PLA /CS/GP composites can reach 4.2 MPa when the addition of CS and GP is 2phr and 4phr, respectively. The self-healing effectiveness of the ENR/PLA/CS/GP composite reaches up to 78% after 3 h at 130 degrees C. The stress intensity of the original ENR/PLA composite is 3.4Mpa, and that of healing ENR/PLA/CS/GP composite is 3.3Mpa. Meanwhile, the peak heat release rate (HRR) of ENR/PLA could decease 35.8% owing to 2phr CS and 4phr GP.