| The aliphatic polyamide has excellent mechanical properties and excellent processing properties,but has poor thermal properties.The wholly aromatic polyamide has excellent thermal properties but poor processing properties.Semi-aromatic polyamide can combine the advantages of both,and is a material that not only has good processing properties but also good heat resistance,and is the most cost-effective option.In the semi-aromatic polyamide10 T,one of the monomers,the quinone diamine,is derived from the renewable resource ramie,and the bio-based content is as high as 56.3%.However,due to its narrow processing window,the third component polyamide 10 I segment is introduced to widen the processing window and improve the processing performance.In this paper,the salt formation process and prepolymerization process of polyamide10T/10 I were studied.The polyamide 10T/10 I salt and prepolymer were determined by infrared spectroscopy.Then,the polyamide 10T/10 I with different 10 I segment content was directly prepared by one-step melting method,and the optimal polymerization process was determined.The thermal properties,non-isothermal crystallization kinetics and mechanical properties of polyamide 10T/10 I were also studied.The thermal performance results show that with the increase of 10 I segment content,the heat distortion temperature and melting temperature of polyamide 10T/10 I gradually decrease,while the glass transition temperature increases first and then decreases.When the amount of the 10 I segment is less than 10%,the melting temperature of the polyamide is still above300 ℃.And when the amount is more than 25%,the melting temperature is lowered to280 ℃.When the amount of the 10 I segment added is 7% or less,the heat distortion temperature of the polyamide does not change much,and is close to about 10%,and the glasstransition temperature is maintained at about 120 °C.The degradation behavior of polyamide belongs to one-step degradation.The addition amount of 10 I segment has little effect on decomposition temperature,and is about 350 °C.The non-isothermal crystallization kinetics of the polymer was studied by the Jeziorny method and the Mo method.The results show that in the early stage of crystallization,the growth mode of the polyamide 10T/10 I crystal is one-dimensional fibrous growth and two-dimensional sheet growth coexist.The increase in the content of the 10 I segment increases the crystallization time of the polymer.At the end of crystallization,the polymer crystallizes at a slower rate and the crystallization mode is more complicated.The F(T)value and the alpha value of the non-isothermal crystallization of the polymer were calculated by the Mo method.The non-isothermal crystallization activation energy of polyamide 10T/10 I was calculated by Kissinger method and Takhor method.The mechanical properties show that the tensile strength,flexural strength and impact strength of the polymer show a trend of decreasing first and then increasing with the increase of 10 I segment content.When the content of 10 segments is 10%,the comprehensive mechanical properties are the best.Compared with the polyamide 10 T,the tensile strength is increased by about 20%,the bending strength is increased by about 30%,and the impact strength is increased by about 16%.The density and water absorption of the polyamide10T/10 I did not change much,the density was about 1.20 g/cm-3,and the water absorption rate was about 0.3%.The melt index of the polyamide 10T/10 I gradually increases as the 10 I segment increases. |
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