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Study On The Modification Of ADC Blowing Agent And Research Of Foaming Behavior In EVA

Posted on:2012-02-29Degree:MasterType:Thesis
Country:ChinaCandidate:J ZhangFull Text:PDF
GTID:2211330368958567Subject:Materials Science and Engineering
Abstract/Summary:PDF Full Text Request
Azodicarbonamide is used extensively in industry as a blowing agent for foaming plastics. But ADC blowing agent used alone can't meet the requirement of the market because of its higher decomposition temperature, hence ADC blowing agent modified by activator can satisfied different types of plastics materials'requirements and increased the added value of products. This thesis takes ADC blowing agent as research subject. Firstly, the mechanism of ADC was studied by using modern research methods and the thermal decomposition mechanism was concluded which provides the theory and guides function for the next study of modification; Secondly, the modifiers were optimized in order to increasing ADC's decomposition rate, reducing the residue, improving the gas evolution and changing ADC's decomposition temperature, so they can satisfy different foaming materials'requirements and improve ADC's quality; Finally, modified ADC which satisfied process requirement of EVA were screened out and the influence of EVA foam product's mechanical properties and bubble pore structure with ADC were investigated.1,The thermal decomposition mechanism of azodicarbonamide was investigated by characterizing gases and residues with TG-MS, DSC, IR. The results showed that the azodicarbonamide underwent a three-stage decomposition process:the first stage decomposition gaseous products are N2, CO and HNCO, correspondingly the residue is biurea; the second stage decomposition gaseous products are NH3 and HNCO; the third stage decomposition gaseous products are NH3 and CO2, correspondingly, the residue is urazole.2,The influences of decomposition temperatures, decomposition rate and gas evolution of ADC blowing agent modified with containing zinc and organic acids activator were studied by self-designed blowing agent decomposition testing device. Influence of the decomposition thermodynamics of ADC blowing agent with containing zinc or organic acids activator were investigated by DSC. The results showed that ADC blowing agent's thermal decomposition temperature was reduced at different degree by adding zinc compounds, and most significant activator was zinc acetate. And the degree of activation order is like this: zinc acetate> zinc oxide> carbonate zinc> zinc stearate; Whereas, ADC blowing agent's thermal decomposition temperature wasn't reduced obviously by adding organic acids. And the degree of activation order is like this:citric acid> salicylic acid> benzoic acid>stearic acid.3,In this work, the modified ADC was used as a blowing agent, CaCO3 was used as nucleating agent, DCP was used as cross linking agent, And the influence of apparent density, tensile strength and elongation at break of EVA foam material with different components and contents of blowing agent, nucleating agent and cross linking agent were studied. The result showed that when EVA attained 100 phr, HSt attained 2.5 phr, DCP attained 0.8 phr, CaCO3 attained 10 phr, modified ADC attained 2.7 phr, the foam material would have a better comprehensive performance.
Keywords/Search Tags:ADC blowing agent, thermal decomposition mechanism, decomposition temperature, gas forming amout, EVA
PDF Full Text Request
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