Preparation And Study Of Low Protein Natural Latex Foam Sponge

Natural rubber latex foam sponge has many characteristics,such as good rebound buffer performance and compression resistance.However,due to the presence of a small amount of protein and other allergens in natural rubber latex,a little of people will have allergies when using natural rubber latex products.Therefore,in this paper,after optimizing the foaming process of natural rubber latex,low protein natural rubber latex foam sponge was prepared by adding arginine and phospholipid into deproteinized latex.The mechanical strength of natural rubber latex foaming materials were improved;the action principle of arginine and phospholipid in the foaming process of low protein natural rubber latex was explored;the effects of different parts of arginine and phospholipid on different properties of low protein natural rubber latex foaming sponge were analyzed.It has important theoretical and practical significance to expand the application scope of natural rubber latex foam sponge while maintaining the excellent elastic properties of natural rubber latex foam products.The results are as follows by experimental research and analysis:(1)In this paper,natural rubber latex foams were prepared with concentrated natural rubber latex as matrix and potassium oleate as foaming reagent.The outcomes displayed that when the content of foaming agent is 1.5%,the foaming temperature is 120?and the vulcanizng time is 25 min,the density of natural rubber latex foam is 0.18 g/cm³-0.20g/cm³,the foam cell was well-distributed and the mechanical properties were outstanding.The tensile strength is 0.30 MPa,the rebound rate is 95.2%,and the compression permanent deformation is 25.2%,the initial degradation temperature is 316.2?,temperature of the fastest degradation rate is 380.6?.The natural latex/MXene composite foaming spongeis prepared by adding two-dimensional material MXene into natural latex.While ensuring the sponge rebound rate is more than 95%,the tensile strength of the foaming material reached 0.60 MPa,and the electrical conductivity and electromagnetic shielding properties is obtained.(2)Low protein natural latex is obtained by centrifugation with protease,low protein natural latex/arginine composite foaming sponge is prepared.Due to the removal of non-rubber components such as protein,low protein natural rubber latex foams have poor properties,with tensile strength of 0.08 MPa,rebound rate of 77.5%,ccompression permanent deformation of 43.6%and storage modulus of 1255 MPa,the initial degradation temperature is 312.8?,temperature of the fastest degradation rate is 375.5?.In low protein natural rubber latex/arginine foam sponge,XPS and FTIR analysis showed that-C=N-group in arginine could form a coordination complex with accelerator ZDC and Zn²⁺in ZnO,which increased the solubility of zinc oxide in the vulcanization system and played a role in promoting sulfurization.When the content of arginine reached 3.0%,the tensile strength of the composite foam reached 0.28 MPa,the rebound rate was 91.6%,the compression permanent deformation was 28.5%,and the storage modulus was 2138 MPa,the initial degradation temperature is 315.0?,temperature of the fastest degradation rate is 378.4?.(3)Low protein natural rubber latex/phospholipid composite foam sponge was prepared by adding phospholipid into low protein natural rubber latex.FTIR analysis showed that the phosphate group formed by phospholipid hydrolysis could form a coordination complex with ZDC and Zn²⁺in ZnO,which could increase the solubility of ZnO in the vulcanization system and promote the vulcanization.When the phospholipid content reached 2.0%,the tensile strength of the composite foam reached 0.25 MPa,the rebound rate was 89.6%,the compression permanent deformation was 30.5%,and the storage modulus was 1761 MPa,the initial degradation temperature is 314.4?,temperature of the fastest degradation rate is 378.2?.