热固型PRF树脂制备及其对胶合防腐竹材剪切强度影响

Preparation and Properties of Hot Curing PRF Resin

为满足经防腐处理的竹结构材胶合强度的要求,合成了系列低质量分数间苯二酚的热固型苯酚-间苯二酚-甲醛（PRF）树脂,应用于粘接防腐处理的竹材。结果表明：随着合成树脂中间苯二酚质量分数的增加,树脂的溶水倍数显著增加,树脂密度先减少后增加;随着甲醛与苯酚摩尔比的增加,树脂的游离甲醛质量分数显著增加,固体质量分数减小,树脂密度先减少后增加。PRF树脂用于胶合防腐处理的竹片,剪切强度值比无间苯二酚的酚醛树脂（RF）增加200%以上,间苯二酚质量分数在1%-4%范围内变化,对树脂剪切强度影响不明显。综合性价比与环保要求,优化的PRF树脂的间苯二酚质量分数为1.0%、甲醛与苯酚摩尔比为1.6∶1.0。

In order to increase the bonding strength of the hot curing resin used on bamboo,we used the resorcin to modify the PF resin into hot curing PRF resin. With the increase of resorcin content,the water miscibility of the resin rose significantly and the density declined first and rose at last,and the solid content and formaldehyde free percent of resin changed a little. The changes of molar ratio of formaldehyde and phenol affected the formaldehyde free percent and the solid content of resin seriously.With the rising of molar ratio of formaldehyde and phenol,the free formaldehyde increased and the solid content of resin decreased obviously. We compared the shear strengths of bonding bamboo specimen treated by wood preservatives between PF and PRF. The shear strengths bonded by PRF increased by 200%. However,when the resorcin content of PRF resin changed in 1%-4%,the shear strength changed a little. The optimized resorcin content was 1.0%,and the molar ratio of formaldehyde and phenol was 1.6 ∶ 1.