An experimental procedure was designed to monitor the preform thickness change real-time throughout the vacuum assisted resin infusion( VARI) process. Two kinds of liquid with different viscosity were infused with dif...An experimental procedure was designed to monitor the preform thickness change real-time throughout the vacuum assisted resin infusion( VARI) process. Two kinds of liquid with different viscosity were infused with different post-filling time. The variation of the part thickness during the VARI process was studied. And the effect of the post-filling time on the part thickness was investigated.The results indicate that the compaction behavior of the preform can be divided into three stages,and the fiber volume fraction varies with the post-filling time in a similar sinusoid form. In addition,the post-filling should be overtime for the greatest fiber volume fraction,and when the resin is infused with higher viscosity,the greatest fiber volume fraction is higher.展开更多
The most common process to manufacture advanced composites is the costly autoclave.One of the out-of-autoclave alternatives is the low-cost vacuum assisted resin infusion(VARI)which produces quality parts with less po...The most common process to manufacture advanced composites is the costly autoclave.One of the out-of-autoclave alternatives is the low-cost vacuum assisted resin infusion(VARI)which produces quality parts with less pollution.Epoxy resin is a widely used composite matrix resin,but its high flammability limits its use as interior composite parts for vehicles.The usual flame retardant for epoxy involves halogen,which is effective but has high smoke toxicity.As a result,halogen-free flame retardant epoxy resin systems become dominant.In this paper,phosphorus flame retardant was combined with benzoxazine(BOZ)to produce synergistic effect and achieve satisfactory flame retardance,as well as mechanical improvement for the epoxy resin.Differential scanning calorimetry(DSC),dynamic mechanical analysis(DMA),thermal gravitational analysis(TGA),the cone calorimeter(CC),and limiting oxygen index(LOI)were used to characterize the resins.The results showed significant improvement on the flame retardance of the synergistically modified resins.Specifically,the carbon residue increased by 113.6%,and the char thickness increased by 6 to 7 times,compared to those of the flammable benchmark resin.The LOI reached 33 and passed the UL94 V-0 vertical burn rating.The modified resins also exhibited adequate stability and viscosity suitable for VARI processes.展开更多
采用纳米碳酸钙(CaCO_3)浸渍改性工艺对竹浆纤维(BPF)进行改性,并采用真空辅助树脂浸注(VARI)技术制备纳米浸渍改性竹浆纤维(IMBPF)/环氧树脂复合材料.利用热失重分析(TGA)方法研究了原材料和复合材料在氮气气氛下的热降解行为,采用Flyn...采用纳米碳酸钙(CaCO_3)浸渍改性工艺对竹浆纤维(BPF)进行改性,并采用真空辅助树脂浸注(VARI)技术制备纳米浸渍改性竹浆纤维(IMBPF)/环氧树脂复合材料.利用热失重分析(TGA)方法研究了原材料和复合材料在氮气气氛下的热降解行为,采用Flynn-Wall-Ozawa(FWO)和Vyazovkin and Weight(VW)方法量化了复合材料的表观活化能.结果表明:IMBPF/环氧树脂复合材料出现300~400,400~450,600~700℃3个失重区,分别对应BPF、环氧树脂和纳米CaCO_3的热降解;采用FWO法和VW法测定的IMBPF/环氧树脂复合材料的表观活化能均高于对照样(未改性的BRF),且FWO法估算数值高于VW法;纳米CaCO_3对复合材料的热降解特性具有调控作用;FWO法和VW法处理的结果总体相差不大,但前者优于后者.展开更多
基金The Fundamental Research Funds for the Central Universities,China(No.2232014D3-26)Innovation Fund of the Chinese National Engineering Research Center,China(No.SAM C14-JS-15-049)Science and Technology Commission of Shanghai Municipality,China(No.14DZ1100402)
文摘An experimental procedure was designed to monitor the preform thickness change real-time throughout the vacuum assisted resin infusion( VARI) process. Two kinds of liquid with different viscosity were infused with different post-filling time. The variation of the part thickness during the VARI process was studied. And the effect of the post-filling time on the part thickness was investigated.The results indicate that the compaction behavior of the preform can be divided into three stages,and the fiber volume fraction varies with the post-filling time in a similar sinusoid form. In addition,the post-filling should be overtime for the greatest fiber volume fraction,and when the resin is infused with higher viscosity,the greatest fiber volume fraction is higher.
文摘The most common process to manufacture advanced composites is the costly autoclave.One of the out-of-autoclave alternatives is the low-cost vacuum assisted resin infusion(VARI)which produces quality parts with less pollution.Epoxy resin is a widely used composite matrix resin,but its high flammability limits its use as interior composite parts for vehicles.The usual flame retardant for epoxy involves halogen,which is effective but has high smoke toxicity.As a result,halogen-free flame retardant epoxy resin systems become dominant.In this paper,phosphorus flame retardant was combined with benzoxazine(BOZ)to produce synergistic effect and achieve satisfactory flame retardance,as well as mechanical improvement for the epoxy resin.Differential scanning calorimetry(DSC),dynamic mechanical analysis(DMA),thermal gravitational analysis(TGA),the cone calorimeter(CC),and limiting oxygen index(LOI)were used to characterize the resins.The results showed significant improvement on the flame retardance of the synergistically modified resins.Specifically,the carbon residue increased by 113.6%,and the char thickness increased by 6 to 7 times,compared to those of the flammable benchmark resin.The LOI reached 33 and passed the UL94 V-0 vertical burn rating.The modified resins also exhibited adequate stability and viscosity suitable for VARI processes.
文摘采用纳米碳酸钙(CaCO_3)浸渍改性工艺对竹浆纤维(BPF)进行改性,并采用真空辅助树脂浸注(VARI)技术制备纳米浸渍改性竹浆纤维(IMBPF)/环氧树脂复合材料.利用热失重分析(TGA)方法研究了原材料和复合材料在氮气气氛下的热降解行为,采用Flynn-Wall-Ozawa(FWO)和Vyazovkin and Weight(VW)方法量化了复合材料的表观活化能.结果表明:IMBPF/环氧树脂复合材料出现300~400,400~450,600~700℃3个失重区,分别对应BPF、环氧树脂和纳米CaCO_3的热降解;采用FWO法和VW法测定的IMBPF/环氧树脂复合材料的表观活化能均高于对照样(未改性的BRF),且FWO法估算数值高于VW法;纳米CaCO_3对复合材料的热降解特性具有调控作用;FWO法和VW法处理的结果总体相差不大,但前者优于后者.
