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林业科学 ›› 2018, Vol. 54 ›› Issue (11): 87-95.doi: 10.11707/j.1001-7488.20181113

• 论文与研究报告 • 上一篇    下一篇

耐热增韧型硼酸/热解油共改性酚醛树脂合成工艺

徐平平1, 周玉成2, 虞宇翔1, 杨科研1, 常建民1   

  1. 1. 北京林业大学材料科学与技术学院 北京 100083;
    2. 山东建筑大学信息与电气工程学院 济南 250101
  • 收稿日期:2018-04-02 修回日期:2018-10-29 出版日期:2018-11-25 发布日期:2018-12-04
  • 基金资助:
    泰山学者优势特色学科人才团队(2015162)。

Synthetic Technology of Heat-Resistant and Toughening Phenol Formaldehyde Resin Co-Modified by Bio-Oil and Boric Acid

Xu Pingping1, Zhou Yucheng2, Yu Yuxiang1, Yang Keyan1, Chang Jianmin1   

  1. 1. College of Materials Science and Technology, Beijing Forestry University Beijing 100083;
    2. School of Information and Electrical Engineering, Shandong Jianzhu University Jinan 250101
  • Received:2018-04-02 Revised:2018-10-29 Online:2018-11-25 Published:2018-12-04

摘要: [目的]采用硼酸和热解油对酚醛(PF)树脂进行共改性,研发一种地采暖地板用耐热增韧型改性酚醛(BBPF)树脂,以满足地采暖地板长期处于相对高温和潮湿的环境对胶黏剂的特殊要求。[方法]以树脂固体含量、残碳率、拉伸强度和胶合强度为考察指标,以热解油替代苯酚比例、硼酸添加量(占苯酚质量百分比)和氢氧化钠/苯酚(NaOH/P)摩尔比为考察因素,采用正交试验方法,优化BBPF树脂合成工艺。[结果]1)正交试验极差分析表明,BBPF树脂固体含量、拉伸强度和胶合强度的影响因素主次顺序均为热解油替代苯酚比例、硼酸添加量、NaOH/P摩尔比;BBPF树脂残碳率的影响因素主次顺序为热解油替代苯酚比例、NaOH/P摩尔比、硼酸添加量。2)随热解油替代苯酚比例提高,BBPF树脂固体含量、残碳率和胶合强度均呈下降趋势,拉伸强度呈上升趋势;随硼酸添加量增大,BBPF树脂固体含量、残碳率、拉伸强度和胶合强度均先增大后减小;随NaOH/P摩尔比增大,BBPF树脂固体含量、残碳率和胶合强度均先升高后降低,拉伸强度升高。3)BBPF树脂的优化合成工艺为热解油替代苯酚比例20%、硼酸添加量4%、NaOH/P摩尔比0.5,此工艺下合成的BBPF树脂残碳率在800℃下高达58.10%,其胶膜拉伸强度为3.15 MPa,断裂伸长率为15.7%,胶合强度为1.12 MPa。4)热重分析表明,在0~800℃范围内,树脂质量损失分为4个阶段:第1阶段为30~350℃,树脂中残余水分蒸发,同时伴有树脂后固化,未参与固化的羟甲基被氧化脱除,醚键裂解转化为亚甲基键,甲醛释放,BBPF树脂失重速率极值向高温区移动;第2阶段为350~450℃,树脂中亚甲基键断裂分解,质量损失量较少;第3阶段为450~600℃,酚羟基脱水环化,树脂明显分解,BBPF树脂最大失重速率的温度高于PF树脂和热解油酚醛(BOPF)树脂,低于硼酚醛(BPF)树脂;第4阶段为600~800℃,BBPF树脂在800℃的残碳率高于PF树脂与BOPF树脂,低于BPF树脂。傅里叶变换红外光谱分析显示,BBPF树脂与BOPF树脂的红外光谱在3 420 cm-1处的羟基O-H峰强度略低于PF树脂,且峰变窄;在1 384 cm-1存在B-O键吸收峰,2 924 cm-1处的CH2特征峰、1 047 cm-1处的醚键吸收峰和876 cm-1处的苯环取代基位置峰强度均增强。[结论]采用硼酸和热解油共改性酚醛树脂,硼酸与酚羟基反应可引入高键能的B-O键,热解油的添加可引入柔性分子链段,同时可提高树脂体系交联度、耐热性和韧性。

关键词: 酚醛树脂, 硼酸, 热解油, 地采暖地板, 耐热性, 韧性

Abstract: [Objective] The phenolic resin was co-modified with boric acid and bio-oil to prepare a heat-resistant and toughening phenol formaldehyde resin, which can chronically satisfy the special requirements of the wood flooring used in a relatively high temperature and humid environment.[Method] The optimum technology of phenolic resin co-modified by boric acid and bio-oil(BBPF resin) was put forward based on examining index on the solid content, carbon residue rate, tensile strength and bond strength as well as examine factors on the substitute rate of bio-oil to phenol, the addition of boric acid and NaOH/P.[Result] 1) Range analysis of the orthogonal experiment showed that the substitute rate of bio-oil to phenol has the greatest influence on the solid content, tensile strength and bond strength of the BBPF resin, followed by the addition of boric acid to phenol and the molar ratio of NaOH/P among the main factors. While the substitute rate of bio-oil to phenol had the most pronounced influence on the residual carbon rate of the BBPF resin, followed by the molar ratio of NaOH/P and the addition of boric acid among the main factors. 2) With the increase of the substitute of bio-oil to phenol, the solid content and residual carbon rate of the BBPF resin both showed a downward trend, so as the bond strength of the plywood, but the tensile strength exhibited an increasing trend. Meanwhile, the solid content, residual carbon rate, tensile strength and bond strength increased first and then decreased along with the addition of boric acid. In addition, the solid content, residual carbon rate and bond strength increased initially and then decreased while the tensile strength increased due to the increase of NaOH/P molar ratio. 3) The optimum synthesis process of the BBPF resin was as follows:the substitute rate of bio-oil was 20%, the addition of boric acid to phenol was 4% and the molar ratio of NaOH/P was 0.5. Resin prepared under the optimum condition had a residual carbon rate of 58.10% at 800℃, and a tensile strength of 3.15 MPa, an elongation at break of 15.7%, the bond strength was 1.12 MPa. 4) The results of thermogravimetric analysis showed that the mass loss of the resins was divided into four stages in the range of 0-800℃. The first stage was 30-350℃. In this stage, the residual moisture in the resin evaporated, along with the post-curing of the resin. The hydroxymethyl group which was not involved in curing was oxidized and then removed. Meanwhile, the ether bond was split into methylene bonds which result ing the release of formaldehyde. In addition, the extremum of the weight loss rate of the BBPF resin moved to the high temperature zone. The methylene bond in the resin broke and decomposed and the mass loss was less in the second stage ranging from 350℃ to 450℃. The third stage of 450-600℃, the phenolic hydroxyl group underwent dehydration and cyclization and the resin was decomposed obviously. In this stage, the BBPF resin had a higher temperature on the fastest degradation which was higher than that of PF resin and phenolic resin modified by bio-oil(BOPF) but lower than phenolic resin modified by boric acid(BPF). In the fourth stage, the residual carbon rate of BBPF at 800℃ was higher than that of PF resin and BOPF resin, and lower than that of BPF resin. The infrared spectrum of the BBPF resin showed an absorption peak at 1 384 cm-1 of B-O bond. Simultaneously, the intensity of the CH2 characteristic peak at 2 924 cm-1 was enhanced as well as peak at 876 cm-1 which indicated the replacement of the phenolic active site.[Conclusion] The high-bonding B-O bonds wereintroduced into the BBPF resin owing to the reaction between boric acid and phenolic hydroxyl group. In addition, the flexible groups of bio-oil were also introduced to the BBPF resin. These improved the heat resistance and toughness of the BBPF resin.

Key words: phenolic resin, boric acid, bio-oil, wood flooring for ground with heating system, heat resistance, toughness

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