淀粉-碱木素改性酚醛树脂的粘接性能及固化动力学研究

Bonding properties and curing kinetics of phenolic resins modified with starch and lignin

利用淀粉和碱木素改性酚醛树脂,讨论了各种因素对该胶黏剂所压制的胶合板的胶合强度、甲醛释放量的影响;并采用差示扫描量热（DSC）法探讨了淀粉-碱木素改性酚醛树脂的固化反应过程,运用Kissinger和Ozawa法进行了动力学研究,得到其固化反应活化能,并通过Crane法得到了反应级数.结果表明：该胶所压制的胶合板的胶合强度达到国家一类胶标准要求,甲醛释放量达到国家E1级标准要求;当碱木素用量为质量分数18.00％、羟甲基化产物加入量为质量分数12.00％时,所压制的胶合板的胶合强度最大（其值为1.22 MPa）;而当碱木素用量为质量分数18.00％,羟甲基化产物加入量为质量分数9.00％时,胶合板的甲醛释放量最小（其值为0.32 mg·L-1）.2种方法计算得到活化能的大小顺序是一致的,高质量分数羟甲基的改性酚醛树脂在固化过程中具有的活化能比低质量分数羟甲基的酚醛树脂的要高,意味着高质量分数羟甲基的改性酚醛树脂固化时需要较多热量,所以不宜添加过多羟甲基化产物.反应级数为小数（0.69～0.86）,说明淀粉-碱木素改性酚醛树脂的固化反应是一个复杂反应.

Phenol-formaldehyde(PF) resins were modified with starch and alkaline lignin and then plywood panels were manufactured with these modified PF resins. Differential scanning calorimetry(DSC) was used to determine the curing behavior of the modified phenolic resins, and a kinetic analysis was performed using the Kissinger and the Ozawa Methods. Influence of various factors on bond strength and formaldehyde emissions of the panels were determined. Results showed that, according to the National Standard, bond strength met the requirements for a Grade resin, and formaldehyde emissions of the manufactured panels met the requirements of Grade E1(1.5 mg·L-1). When the alkaline lignin content was 18.0% and addition of a hydroxymethylated product was 12.0%, bond strength reached a maximum of 1.22 MPa. When the alkaline lignin content was 18.0% and the addition of a hydroxymethylated product was 9.0%, formaldehyde emissions reached a minimum of 0.32 mg·L-1. Activation energies from the Kissinger Method were consistent with those calculated by the Ozawa Method. Compared to a lower hydroxymethylate content, resin with a higher hydroxymethylate content had a higher activation energy. Also, curing had nominal reaction orders between 0.69 and 0.86. Thus, with a higher hydroxymethylate content more energy was needed to activate the curing reactions of the resin, and the nominal reaction orders meant that the curing behavior of the modified phenolic resins was complicated. [Ch, 1 fig. 7 tab. 9 ref.]