光固化制备玻璃纤维(GF)增强不饱和聚酯树脂(UPR)复合筋材的研究

采用5种光引发剂体系，通过LED紫外光固化技术制备了玻璃纤维（GF）增强不饱和聚酯树脂（UPR）复合筋材（直径达1.5 cm），进行了热重分析以及力学性能测试，讨论了光引发剂种类及浓度（0.1%~2.0%，质量分数）、紫外光波长（365 nm、395 nm）、光照强度（30~750 mW/cm2）和光照时间对固化及制品性能的影响。结果表明:波长为365 nm的光源具有更好的固化效果；对于给定的引发剂体系，随着光照强度的增加，表观固化时间缩短；巴氏硬度随光照强度的增强而增大，且趋于稳定。在相同的紫外光光照强度下，表观固化时间一般随光引发剂浓度的升高而降低，但对于PI1光引发剂体系，表观固化时间随光引发剂浓度的升高先降低而后又升高。采用PI0或PI5作为光引发剂，紫外固化40 s所得复合材料的拉伸强度达到1 000 MPa，弹性模量达到45 GPa，均优于经热固化所得复合材料，表明，通过LED紫外光固化技术，高效制备厘米级大直径筋材具有可行性。 

Study on Preparation of Glass Fiber(GF)Reinforced Unsaturated Polyester Resin(UPR)Rebar by Light Curing

Five kinds of photoinitiators were used to prepare glass fiber(GF) reinforced unsaturated polyester resin(UPR) rebar with the diameter up to 1.5 cm by LED UV curing technology. The thermogravimetric analysis and mechanical property tests were carried out for the resultant composites and the effects of photoinitiator species and concentration(0.1%~2.0%, mass friction), wavelength of ultraviolet light(365 nm and 395 nm), light intensity(30~750 mW/cm2) and exposure time on the curing and properties were investigated. The results revealed that the light source with wavelength of 365 nm had better curing effect; the apparent curing time was generally shortened with the increase of light intensity for a given initiator; the Barcol hardness increased with the increase of light intensity and became more stable. Under the same ultraviolet light intensity, the apparent curing time generally decreased with the increase of photoinitiator concentration except for PI1 photoinitiator, with which, the apparent curing time decreased first and then increased with the increase of photoinitiator concentration. The tensile strength and the elastic modulus of the composite with PI0 or PI5 photoinitiators after UV exposure of 40 s reached up to 1 000 MPa and 45 GPa, respectively, which were higher than those of the composite by heat curing. These results suggested that the LED UV curing could be an efficient method to prepare GF/UPR rebars with diameter up to centimeter level.