In this study,a novel bio-based thermosetting system has been developed from epoxy resin(EP),with rosin-sourced anhydrides(maleopimaric acid,RAM) as curing agent and imidazole type latent catalyst(two amino imidazole ...In this study,a novel bio-based thermosetting system has been developed from epoxy resin(EP),with rosin-sourced anhydrides(maleopimaric acid,RAM) as curing agent and imidazole type latent catalyst(two amino imidazole salt complex,IMA),to be used as matrix for hot-melt prepreg curing at mid-temperature.For comparison,the epoxy resin system with petroleum sourced hardener methylhexahydrophthalicanhydride(MHHPA) was also examined.The curing behaviour and mechanism were investigated by non-isothermal differential scanning calorimeter(DSC) analysis and Fourier transform infrared(FTIR) spectra.The results showed that the curing course of bio-based epoxy resin system containing RAM included two stages,which were the reaction between the free carboxyl group of RAM and oxirane ring under the acceleration of IMA,and the main reaction attributed to the reaction between anhydride and oxirane.According to Kissinger method,the reaction activation energy(E_a) of two stages were 68.9 and 86.5kJmol^(-1),respectively.The E_a of EP/MHHPA and EP/IMA resin system were 81.04 and 77.9kJmol^(-1).The processing property of EP/RAM/IMA system,i.e.the relationship between viscosity-temperature-time,was characterized by cone-plate viscometer aim to decide the processing parameter of prepreg preparation.The effect of RAM content on mechanical performance and dynamic mechanical property was investigated.Noteworthily,compared with the laminates with EP/MHITPA as matrix,the laminates with RAM as hardeners achieved a 44%,73% and 70℃ increase in bending strength,bending modulus and the glass transition temperature,respectively,due to the bulky hydrogenated phenanthrene ring structure incorporated into the cross-linking networks.When the fiber volume fraction reached 47%,the mechanical property of the laminates prepared with hot melt prepreg was superior or comparable to that of composites with pure petroleum sourced matrix.RAM as cross-linking agent of epoxy resin holds a great potential to satisfy the requirement of composites such as structure and secondary structure parts preparation.展开更多
非热压罐成型(out of autoclave process,OoA)技术是实现结构复合材料低成本制造的有效途径,是当前复合材料研究领域的热点之一。本文介绍了OoA成型复合材料国内外的研究前沿以及在航空航天领域的应用现状,从材料体系和成型工艺两大方...非热压罐成型(out of autoclave process,OoA)技术是实现结构复合材料低成本制造的有效途径,是当前复合材料研究领域的热点之一。本文介绍了OoA成型复合材料国内外的研究前沿以及在航空航天领域的应用现状,从材料体系和成型工艺两大方面总结了OoA成型过程中的缺陷控制方法。在OoA预浸料成型技术中,可通过尽量减少树脂体系中挥发物含量、精细调控树脂体系反应和流变特性、控制预浸料中纤维和树脂的浸润程度、优化成型工艺等手段有效降低复合材料的孔隙率等缺陷。展开更多
基金supported by the China-EU co-funded project ECO-COMPASS(Grant No.MJ2015-HG-103)
文摘In this study,a novel bio-based thermosetting system has been developed from epoxy resin(EP),with rosin-sourced anhydrides(maleopimaric acid,RAM) as curing agent and imidazole type latent catalyst(two amino imidazole salt complex,IMA),to be used as matrix for hot-melt prepreg curing at mid-temperature.For comparison,the epoxy resin system with petroleum sourced hardener methylhexahydrophthalicanhydride(MHHPA) was also examined.The curing behaviour and mechanism were investigated by non-isothermal differential scanning calorimeter(DSC) analysis and Fourier transform infrared(FTIR) spectra.The results showed that the curing course of bio-based epoxy resin system containing RAM included two stages,which were the reaction between the free carboxyl group of RAM and oxirane ring under the acceleration of IMA,and the main reaction attributed to the reaction between anhydride and oxirane.According to Kissinger method,the reaction activation energy(E_a) of two stages were 68.9 and 86.5kJmol^(-1),respectively.The E_a of EP/MHHPA and EP/IMA resin system were 81.04 and 77.9kJmol^(-1).The processing property of EP/RAM/IMA system,i.e.the relationship between viscosity-temperature-time,was characterized by cone-plate viscometer aim to decide the processing parameter of prepreg preparation.The effect of RAM content on mechanical performance and dynamic mechanical property was investigated.Noteworthily,compared with the laminates with EP/MHITPA as matrix,the laminates with RAM as hardeners achieved a 44%,73% and 70℃ increase in bending strength,bending modulus and the glass transition temperature,respectively,due to the bulky hydrogenated phenanthrene ring structure incorporated into the cross-linking networks.When the fiber volume fraction reached 47%,the mechanical property of the laminates prepared with hot melt prepreg was superior or comparable to that of composites with pure petroleum sourced matrix.RAM as cross-linking agent of epoxy resin holds a great potential to satisfy the requirement of composites such as structure and secondary structure parts preparation.
文摘非热压罐成型(out of autoclave process,OoA)技术是实现结构复合材料低成本制造的有效途径,是当前复合材料研究领域的热点之一。本文介绍了OoA成型复合材料国内外的研究前沿以及在航空航天领域的应用现状,从材料体系和成型工艺两大方面总结了OoA成型过程中的缺陷控制方法。在OoA预浸料成型技术中,可通过尽量减少树脂体系中挥发物含量、精细调控树脂体系反应和流变特性、控制预浸料中纤维和树脂的浸润程度、优化成型工艺等手段有效降低复合材料的孔隙率等缺陷。
