The Study Of Micro-cut Tapping With Gas-stimulation On The Properties Of Natural Rubber

Natural rubber(NR)is a natural polymer synthesized by Hevea.It has excellent comprehensive properties and is a very important source of elastomers.It is also an irreplaceable strategic material.China's lack of natural rubber resources,the continuous growth of rubber production for many years are extremely limited,resulting in market demand,strategic reserve stocks and other issues.In recent years,the phenomenon of dead skin disease caused by conventional ethephon-stimulated production and cutting has become increasingly serious.The long-term application of ethephon stimulants has become the main cause of shortening the lifespan of rubber trees.Therefore,the method of micro-cutting and tapping by air traps has attracted the attention of researchers from various countries.The feature of the short cut line of the gas cut micro cut not only reduces the incidence of dead skin disease of the rubber tree,but also makes it have the advantages of less skin consumption and faster cutting speed.However,the properties of natural rubber are closely related to the different cutting methods and the concentration of the reagents used to stimulate the cutting.This study analyzed the non-glue component content,the quality of the raw rubber,the microstructure,rheological properties,and physical and mechanical properties of the natural rubber obtained from different tapping systems.Through different cutting and processing of the rubber tree,samples of non-irritating natural rubber latex,ethephon liquid-stimulating natural rubber latex,and airless micro-cut natural rubber latex were collected.Using weight loss method,EDTA complexometric titration,and Markov's distillation method,a series of characterization methods were used to analyze the effects of different concentrations of stimulation and cutting on the properties of natural latex rubber production,gel removal and colloidal stability.Research shows that stimulation of cutting significantly improves the rubber tree's ability to produce and discharge rubber.Among them,20%of low-concentration air needle microcutting hasthe best yield increase,and the amount of glue produced is 15.98%higher than conventional cutting,which is more effective than conventional ethephon stimulation.The cutting system was improved by 9.57%,and the higher concentration gassy microclimbing was increased by 4.85%.In addition,the content of non-gel components,free calcium and magnesium contents,and volatile fatty acid content in the 20%low-density acne microcutting fresh latex were the lowest.,indicating that the low concentration of gas microemulsion not only yields the highest yield,but also the best colloidal stability.The above latex samples were prepared by natural solidification into raw rubber samples.Atomic absorption spectrophotometer,Kjeldahl nitrogen analyzer,Wallace rapid plasticizer and thermogravimetric analyzer were used to analyze the different concentrations of gas microclimate pairs.Raw rubber quality and performance impact.Studies have shown that the PRI values of 20%ETGNR and 30%ETGNR are larger,indicating that low-concentration prickles have the effect of improving the oxidation resistance of the sample;the thermal initial degradation temperature of 2%ETNR,30%ETGNR,60%ETGNR is low In NR,the thermal initial degradation temperature of 20%ETGNR and 40%ETGNR is consistent with NR,indicating that the stimulation treatment will reduce the thermal stability of some natural rubber.By characterization of the microstructure of natural rubber molecular chains obtained by different stimulators,it can be found that the stimulation treatment reduces the molecular mass of natural rubber,increases the molecular weight dispersion index,and reduces the cross-linking density of rubber;The degree of branching of natural rubber is lower than that of natural rubber without stimulation.Dynamic rheological tests show that the stimulation treatment reduces the elastic modulus,viscosity and viscous flow activation energy of the rubber and increases the flow index of the rubber.Improve the processing rheological properties of the rubber compound.By characterizing the vulcanization characteristics and physical and mechanical properties of the vulcanized natural rubber by different stimuli,it was found that the stimulating treatment improved the vulcanization effect of the compounded rubber,increased the crosslink density of the vulcanizate,and increased the mechanical properties of the vulcanizate.Among them,the non-irritation NR vulcanizate has the lowest mechanical strength,the 20%ETGNR,40%ETGNR,and 60%ETGNR vulcanizates have the highest mechanical strength,and the 20%ETGNR vulcanizates have the highest pull strength,indicating that 20%of the low-concentration pneumoconiosis Micro-cutting samples have both excellent mechanical properties and good anti-aging properties.