酚甲醛膠熱動力分析研究及其應用

Reaction Kinetics Behavior of Phenol Formaldehyde Wood Adhesives by Differential Thermal Analysis and Its Application

鄒哲宗(Che-Tsung Tsoul) ； 尹華文(Hwa-Wen Yin) ； 夏滄琪(Tsang-Chyi Shiah)

《台灣林業科學》 19卷4期 (2004/12) Pp. 297-310

https://doi.org/10.7075/TJFS.200412.0297

摘要

酚甲醛膠合劑為木材工業常用之膠料，瞭解其熱硬化動力學性質有其必要。本研究使用示差掃瞄卡量儀針對模板用酚膠及貨櫃板用酚膠進行量測，由示差掃瞄熱析圖可知，每一試樣只有一個放熱峰，峰值溫度的位置，隨升溫速率增加而增大，並以ASTM Method E698之方法分析，得知升溫速率的對數與峰值溫度的倒數1000/°K為直線相關，符合阿累尼斯方程式。其熱硬化動力學參數值，前者活化能為9064 kJ mole^(-1),阿累尼斯頻率因子的對數值為11.07, 60min半生期90.9℃；後者活化能為1452 kJ mole^(-1)，阿累尼斯頻率因子的對數值為18.33, 60min半生期1012℃。
以台灣杉酚膠膠合材與酚膠貨櫃板為材料，依ASTM D4065-95標準，由多頻率掃瞄方式，測定其彈性模量、粘性模量，與阻尼等粘彈性。並以WLF方程式所研發之時間－溫度重疊軟體，繪圖得知角頻率與彈性模量、粘性模量、阻尼之對數關係，進而求出其在長期經時使用之機械性能變化，並了解處於不同低頻或極高頻刺激下之粘彈特性的變化。其結果之E'、F'及tanδ與0.1~33Hz頻率，由50~200℃之關係圖，獲知E’值隨溫度增加而下降，在超過180℃之後，由於熱劣化的緣故，使其軟化更加迅速，同時也觀察到E”及tanδ急劇上升。

關鍵字

酚甲酸膠 ； 示差掃瞄卡量儀 ； 活化能 ； 粘彈性

並列摘要

Phenol formaldehyde (PF) adhesive resins are frequently used in the wood industry. It is important to understand the relationship of their hardening kinetics. A differential scanning calorimeter (DSC) was used to investigate the thermal properties of PF adhesives for wooden cement molds and container liners. All specimens demonstrated a single exothermic peak from the results of DSC. Peak temperatures rose with an increasing heating rate. According to ASTIVI method E698, logarithmic values of the heating rate were linearly correlated with reciprocal peak temperatures, and correlations fit well with the Arrhenius equation. Polymerization kinetics parameters were measured as follows. Respective values for the activation energies of the cement molds and container liners with PF, were 90.64 and 145.2 kJ mole'; logarithmic values for Arrhenius frequency factors were 11.07 and 18.33; half-life temperatures at 60 mm were 90.9 and 101.2 ℃.
For Taiwania PF-glue-lam and PF container liners, viscoelastic properties, like E' (modulus of elasticity), E'' (modulus of viscosity), and tan S (mechanical damping), were determined by scanning using a multi-frequency method specified by ASTM D-4065-95. Time-temperature superimposing software based on the Williams-Landel-Ferry (WLF) equation was applied to obtain the logarithmic relationship between the angular frequency and the modulus of elasticity, modulus of viscosity, and mechanical damping. Hence, mechanical properties after long-term usage and changes in viscoelastic properties were subject to various low and ultra-high frequency stimulations. Analysis of E', E”, and tan S measurements under 0.1~33 Hz and 50~200℃ demonstrated that E' values decreased with increasing temperature. Over 180℃, thermal degradation accelerated the softening, causing the E” and tan δ values to sharply increase.

並列關鍵字

phenol formaldehyde adhesives ； differential scanning calorimeter ； activation energy ； viscoelastic properties