架橋劑添加量及熱壓溫度對Novolak型酚醛樹脂成型板性質之影響

Effect of Cross-linking Agent Content and Hot-pressing Temperature on the Properties of Moldings Made with Novolak-type Phenol-formaldehyde Resins

楊彝綱(Yi-Gang Yang) ； 李文昭(Wen-Jau Lee)

《林產工業》 31卷4期 (2012/12) Pp. 195-205

https://doi.org/10.6561/FPI.2012.31(4).3

摘要

本研究將化石酚及酚液化柳杉分別與福馬林在酸性條件下反應製備PF及LW-PF兩種Novolak型酚醛樹脂（Phenol-formaldehyde resins; PF），所得合成樹脂以膠體滲透層析儀（Gel permeation chromatography; GPC）分析其分子量分佈，以熱示差掃描卡量儀（Differential scanning calorimeter; DSC）分析其熱熔融性及熱硬化性，以傅利葉轉換紅外線光譜儀（Fourier transform infrared spectroscope; FTIR）分析其樹脂之分子結構特性，由結果得知，PF樹脂有較小的重量平均分子量，較明顯的熱活動性及熱硬化性，較高比例之亞甲基結構；進一步將兩種Novolak樹脂粉與木粉及六亞甲基四胺以不同比例混合，並以150、165及180℃熱壓溫度製作成型板，其中以PF樹脂為結合劑所製作成型板有較低之浸水吸水率及厚度膨脹率，較高之內聚強度、靜曲強度及彈性模數，熱重分析（Thermo-gravimetric analysis; TGA）顯示以PF及LW-PF樹脂為結合劑所製作成型板有相似之熱裂解行為，由其熱裂解速率曲線顯示其熱裂解包含兩個階段，而以LW-PF為結合劑者在較多六亞甲基四胺或較高熱壓溫度所製作成型板有較高之熱抵抗性。

關鍵字

成型板 ； Novolak樹脂 ； 酚醛樹脂 ； 酚液化木材

並列摘要

Two kinds of Novolak-type phenol-formaldehyde resins (PF), namely PF and LW-PF, were prepared by reacting fossil phenol and phenol-liquefied wood with formalin under acid condition, respectively. The molecular weight distribution of the prepared resins was measured with gel permeation chromatography (GPC). The thermo-melting and thermosetting behaviors of the prepared resins were evaluated with differential scanning calorimeter (DSC). The molecular structure characteristic of the prepared resins was detected with Fourier transform infrared spectroscope (FTIR). The experimental results show that PF resin had lower weight-average molecular weight, more obvious in thermo-melting and thermosetting, and higher ratio of methylene structure. In addition, the mixture of Novolak resin powder, wood powder and hexamethylenetetramine with various weight ratios were hot-pressed at 150, 165, and 180℃ to make moldings. The moldings made with PF resin as binder had lower water absorption and thickness swelling, and had higher internal bonding strength, bending strength and elastic modulus. Thermo-gravimetric analysis (TGA) shows that the moldings made with PF and LW-PF as binders had similar thermal degradation behavior. They had a two-stage thermal degradation as shown from the curves of thermal degradation rate. When LW-PF was used as binder, with the addition of more amount of hexamethylenetetramine or higher temperature for hot-pressing, we could obtain the moldings with higher heat resistance.

並列關鍵字

Moldings ； Novolak resins ； Phenol-formaldehyde resins ； Phenol-liquefied wood