酚－間苯二酚－樹皮萃取物－甲醛共聚合樹脂之合成及其性質

Synthesis and Properties of Phenol-Resorcinol-Bark Extractive-Formaldehyde Copolymer Resins

李文昭(Wen-Jau Lee) ； 藍偉銓(Wei-Chuan Lan)

《中華林學季刊》 37卷4期 (2004/12) Pp. 435-444

https://doi.org/10.30064/QJCF.200412.0007

摘要

本研究以相思樹(Acacia confusa)及杉木(Cunninghamia lanceolata)樹皮之鹼萃取物為原料，探討二階段合成法製備常溫硬化型酚(P)－間苯二酚(R)－樹皮萃取物(T)－甲醛(F)共聚合樹脂(PRTF-B)之可行性。共聚合樹脂合成時乃先將酚與甲醛於酸性環境下進行第一階段反應，形成novolac型PF預聚合樹脂，隨後於鹼性環境下加入相對量甲醛，使其在PF預聚合樹脂之分子鏈上或末端進行加成反應產生羥甲基，隨後再加入樹皮萃取物及間苯二酚進行第二階段之共聚合反應。由試驗結果得知，PRTF-B共聚合樹脂中仍須有足夠的間苯二酚始可具備常溫硬化性，以相思樹樹皮萃取物為原料者，在P/(R+T)=1/1時，間苯二酚與樹皮萃取物之比例為25/75者具常溫硬化性，而以杉木樹皮萃取物為原料者，則間苯二酚與樹皮萃取物之比例則須50/50始具有常溫硬化性。常溫硬化型PRTF-B共聚合樹脂所需之膠化時間較PRF樹脂縮短。以DSC分析顯示其硬化過程為一放熱反應，且在硬化劑添加後之初期反應較為明顯，隨後即趨於平緩，以杉木樹皮萃取物為原料之PRTF-B7共聚合樹脂有較明顯之放熱峰。FT-IR光譜分析顯示PRTF共聚合樹脂與PRF樹脂有相似之分子構造。以相思樹樹皮萃取物為原料之PRTF-B1、B3共聚合樹脂之常態膠合強度與PRF者相當，溫水浸水之膠合強度則明顯提高。

關鍵字

樹皮萃取物 ； 膠合性能 ； 常溫硬化 ； 酚－間苯二酚－樹皮萃取物－甲醛共聚合樹脂

並列摘要

The alkaline extractives extracted from the bark of Taiwan acacia (Acacia confusa) and China fir (Cunninghamia lanceolala) were used as raw materials in this study. The feasibilities and properties of phenol-resorcinol-bark extractive-formaldehyde copolymer resins (PRTF) prepared with two stages synthesis method were investigated. As PRTF copolymer resins synthesized, phenol reacted with formaldehyde at the first stage under the acid condition to form the liner novolak PF prepolymer. And then the additional formaldehyde was added under alkaline condition to bring the hydroxymethyl group at the molecular chain or molecular end of the PF prepolymer by additional reaction. Afterward, bark extractives and resorcinol were added simultaneously to undergo the secondary stage reaction of copolymerization. From the results, it was found that sufficient resorcinol was needed for PRTF copolymer resins to have cold-setting property. The PRTF copolymer resins made from Taiwan acacia bark extractives with P/(R+T)=1/1 had cold-setting capability at the ratio of resorcinol to bark extractives was 25/75, but 50/50 was needed for China fir bark extractives to have cold-setting property. The PRTF copolymer resins that could harden at room temperature had gel time shorter than PRF resin. The DSC analysis showed that the cold-setting process of PRTF copolymer resins was an exothermic reaction, and the heat flow appeared mainly at the initial stage after the hardener added, and then trended to relax. The PRTF-B7 copolymer resin made from China fir bark extractives had the exothermic peak more obvious than those made from Taiwan acacia bark extractives. The FT-IR analysis showed that PRTF copolymer resin and PRF resin had similar molecular structure. The PRTF-B1 and PRTF-B3 copolymer resins made from Taiwan acacia bark extractives had the dry bonding strength the same as PRF, and had the better wet bonding strength than PRF.

並列關鍵字

Bark extractive ； Bonding property ； Cold-setting ； Phenol-resorcinol-bark extractive-formaldehyde copolymer resin