農林廢料製造木材膠合劑之研究（Ⅵ）酚－相思樹樹皮萃取物－甲醛共聚合樹脂之熱硬化性

Studies on the Manufacture of Wood Adhesives from the Residue of Agriculture and Forest (VI) - the Properties of Thermosetting of Phenol-Acacia Bark Extractive-Formaldehyde Copolymer Resins

李文昭(Wen-Jau Lee) ； 劉正字(Cheng-Tzu Liu)

《林產工業》 17卷1期 (1998/03) Pp. 197-218

https://doi.org/10.6561/FPI.1998.17(1).14

摘要

本研究乃利用熱示差掃描卡量（DSC）探討不同合成條件之酚甲醛樹脂（PF）及酚－相思樹樹皮萃取物－甲醛共聚合樹脂（PTF）之熱硬化特性。試驗結果顯示各合成樹脂熱硬化時其速率常數之對數（In K）與溫度之倒數（1/T）成直線關係，因此可利用Borchardt及Daniel之n次反應模式分析其熱硬化反應。PF樹脂在DSC熱分析時只有一放熱峰出現，增加合成時之縮合反應時間，則其樹脂液熱硬化時之最高放熱峰溫度及反應、活化能略為提高，硬化反應熱則明顯減少，而NaOH含量較多者有較高之最高放熱峰溫度，硬化反應熱則較少。PTF共聚合樹脂熱硬化時之最高放熱峰溫度及硬化反應熱均較PF樹脂低，且其合成時NaOH/P之莫耳比愈小者，加成反應之速度愈慢，而NaOH含量愈高者，最高放熱峰溫度及硬化反應熱愈大。萃取物取代量增加時，加成反應之速度減慢，熱硬化之硬化反應熱明顯減少，最高放熱峰溫度則無明顯變化。縮合程度較高之樹脂應用於較低之加熱溫度時，其所需之硬化時間較縮合程度低者為長，然在較高加熱溫度時則二者所需之加熱時間差異不大。

關鍵字

酚－萃取物－甲醛共聚合樹脂 ； 熱示差掃描卡量 ； 熱硬化 ； 硬化反應熱

並列摘要

The thermosetting behaviors of phenol-formaldehyde resins (PF) and phenol-acacia bark extractive-formaldehyde copolymer resins (PTF) with various synthesis condition had been investigated through Differential Scanning Calorimetry (DSC). The linearity of the Arrhenius plots of InK vs 1/T for all resins at thermosetting justified the use of the Borchardt and Daniel's nth order model to characterize the curing reaction of thermoset. There had only one exothermic peak appeared for PF resins at DSC thermograms. Extended the condensation reaction time of PF resins, the maximun temperature of exothermic peak and activation energy of the thermolsetting reaction would increase, but the heat of curing reaction would decrease significantly. Increament of the amount of NaOH would increase the maximun temperature of the exothermic peak, and decrease the heat of curing reaction of PF resins. The maximun temperature of exothermic peak and the heat of curing reaction would lower for PTF copolymer resins than PF resins. For PTF copolymer resins, smaller the molar ratio of NaOH/phenol, slower rate of addition reaction had, and the larger amount of NaOH, the higher maximun temperature of exothermic peak and heat of curing reaction had. Increament of the amount of extractive replacement would slow down the addition reaction rate and decrease the heat of curing reaction, but there had no influence upon the maximun temperature of exothermic peak. When lower heating temperature had been used for the resins with higher degree of condensation, more longer of setting time would be needed than those of lower degree, but when used at higher heating temperature, time needed for them were the same.

並列關鍵字

phenol-extractive-formaldehyde copolymer resins ； Differential Scanning Calorimetry (DSC) ； thermoset heat of curing reaction