碳素纤维浸渍增重改性酚醛树脂

本文叙述了一种低粘度、高固体含量的改性酚醛树脂作碳索纤维和其他碳索材料的浸渍剂。测试其固化性能及碳化后的碳化收率，并对比实验用普通酚醛树脂、醚化酚醛树脂、呋喃树脂，选择最优性能的树脂。并对该改性酚醛树脂做储存稳定性实验。     

PF树脂对杉木浸渍与压缩工艺的研究

为了改善杉木材质软、强度低等物理力学性能方面存在的一些缺陷,用PF(酚醛)树脂溶液对杉木进行浸渍压缩的改性处理。试验结果表明,当浸胶浓度为25%、浸胶时间为24h、热压温度为160℃和每单位厚度的保压时间为45s/mm时,所得改性杉木的性能最佳。     

杉木浸渍阻燃处理配方及工艺优化

以进口杉木为原材料,以碳酸氢铵、多聚磷酸钠、硼酸组成木材浸渍阻燃剂,以氧指数(OI)、烟密度等级(SDR)和处理成本为综合考核指标,通过正交试验法优化阻燃处理的配方和工艺条件。结果表明:碳酸氢铵20 g/L、多聚磷酸钠20 g/L、硼酸60 g/L、60℃下常压浸渍48 h,可达到较佳的阻燃抑烟效果,杉木试样的OI从处理前的21.1%提高至54.5%,SDR从处理前的35.49降至2.17;碳酸氢铵和多聚磷酸钠的浓度对OI和SDR的影响较小,硼酸浓度和温度对OI和SDR的影响较大,硼酸浓度大于30 g/L时,就能达到很好的抑烟效果,SDR都小于5.0,且随着硼酸浓度和浸渍温度的提高,OI呈递增趋势。     

Nomex蜂窝浸渍用酚醛体系的研究

本文介绍一种新的Ｎｏｍｅｘ峰窝浸渍用酚醛树脂ＸＴ－１０，研究了树脂的性能，Ｎｏｍｅｘ蜂窝的浸渍工艺及性能等。     

细结构产品浸渍工序质量稳定性控制

简要概括细结构产品浸渍工序中质量稳定性控制的影响因素,并对浸渍工序中原料、条件、过程因素及其对浸渍工序的影响作简要的分析探讨。     

酚醛树脂浸渍石墨的热稳定性研究

在常温常压的条件下,以酚醛树脂浸渍M120碳石墨材料,研究了不同固化温度条件下浸渍石墨的增重率、开孔气孔率、肖氏硬度及抗折强度等基本性能,并通过马弗炉和热重分析仪分析其热稳定性。结果表明,160℃固化条件下的浸渍石墨试样的基本物理性能最优(增重率最高,开孔气孔率最低,肖氏硬度最高),140℃固化条件下的浸渍石墨试样抗折强度最高,具有优异的热稳定性。酚醛树脂浸渍石墨在0~450℃热稳定性较好,在450℃以上时,浸渍石墨开始分解,热稳定性差。     

微波超声波技术在阻燃剂浸渍处理木材中的应用

将微波处理与超声波辐射技术应用于木材阻燃处理中,利用微波加热处理改善木材构造的渗透性能,利用超声波的空化作用强化阻燃剂浸入性能。以ZR—M-301型木材阻燃剂为浸渍药液,樟子松和水曲柳为木材试样,选择常压浸渍、压力浸渍和微波处理后超声波加压浸渍3种木材阻燃处理方法,考察在生产阻燃木材的浸渍方法中引入微波和超声波技术的可行性,实验表明新的技术路线是可行的。     

几种云南木材液体浸渍行为的研究

研究了几种云南木材在水和有机液体中的浸渍行为 ,探讨了浸渍液体的溶解度参数、木材种类和密度、助浸剂、浸渍时间和压力以及电子束辐射 (EBI)等因素对木材的液体浸渍行为的影响     

酚醛树脂的增韧改性研究进展

综述了酚醛树脂增韧改性的国内外研究现状,归纳了用橡胶、热塑性树脂等外增韧,干性油类、硅烷类、无机酸等内增韧以及纳米材料增韧酚醛树脂的研究方法及发展趋势,同时简要介绍了各种方法的改性机理。     

马来酰亚胺改性酚醛树脂研究进展

综述了近年来马来酰亚胺(MI)对酚醛树脂(PF)的常见改性方法。重点分析和总结了双马来酰亚胺(BMI)改性PF的机制、方法,并介绍了应用新型MI结构聚合物改性PF及PF胶粘剂。最后展望了MI改性PF的未来发展方向。     

纳米材料改性酚醛树脂研究进展

综述了近年来纳米材料改性酚醛树脂(PF)的研究现状。介绍了不同纳米材料(包括碳纳米管、纳米炭黑、纳米碳纤维、纳米金属粒子、纳米弹性粒子、纳米黏土、纳米SiO2和纳米TiO2等)对PF复合材料性能的影响。探讨了纳米材料在改性PF过程中存在的问题,并对纳米材料改性PF的发展趋势作出了展望。     

Moisture transfer and stress development during high-temperature drying of Chinese fir

Abstract

The knowledge of moisture content (MC) and drying stress are crucial parameters to control the drying process and maintain the quality of dried wood. Herein, we investigated the pattern of moisture transfer and stress development in Chinese fir during the high-temperature drying process. The MC in each layer of lumber was separated into bound water and free water via nuclear magnetic resonance (NMR), and the drying and residual stress were measured using prong test method. There was different MC in each layer along the thickness, resulting in an MC gradient that initially increased and then decreased, which is consistent with the trend of drying stress. The T₂₁ peak indicating bound water shifted to the left especially when MC was below the fiber saturation point, signifying that the discharge of moisture became difficult with prolonged drying time. The ratio of bound water to free water was different in each layer, indicating that the moisture transfer was different along the thickness. Furthermore, the residual stress was greater than the corresponding drying stress though the disparity reduced gradually, which suggests that the MC gradient was the largest affecting factor for drying stress at high MC stages but decreased to some extent as the drying process continued.     

ABS改性的研究进展

丙烯腈-丁二烯-苯乙烯(ABS)是一种三元共聚物。由于它的特殊结构,赋予了材料优异物理性能和加工性能。本文主要综述了ABS的各种改性方法,并对未来ABS的改性研究趋势做了简要分析。     

丙烯酸酯改性水性聚氨酯复合乳液的研究进展

综介绍了丙烯酸酯改性水性聚氨酯的几种改性制备方法及其优缺点,其中包括:物理共混改性,交联共混改性,接枝共聚改性,核-壳结构乳液聚合改性,互穿网络法改性等。综述了国内外的研究现状及今后研究发展方向。     

The orthotropic viscoelastic properties of Chinese fir wood during the temperature ramping process

Abstract

In this study, the orthotropic viscoelasticity of Chinese fir wood (Cunninghamia lanceolata [Lamb.] Hook) was investigated during the temperature ramping process. The storage modulus (E′) and loss modulus (E″) of longitudinal (L), radial (R), and tangential (T) specimens with six levels of moisture content (MC) ranging from 0.6 to 22.0% were determined form 20 to 280?°C. The change in E′ was influenced by the dual effects of temperature and MC; the loss of adsorbed water in the wood cell wall caused an increase in wood stiffness. The individual decline in E′ was affected by heating to different degrees and the heating exerted more influence on the transverse specimens and less contribution to the L specimens. Different relaxation processes of E′′ were observed in specimens with different MCs in the three main directions, indicating that the mechanical relaxation of wood was affected by its MC and microstructure. The β and γ-relaxation processes exhibited a conjointly circular arc shape in the transverse directions, which was attributed to the superposition of the transitions of lignin and hemicellulose. A higher α-loss peak temperature (α-T_LP) and intensity of the α-relaxation process were observed in the L specimens than the transverse specimens. The β-T_LP and γ-T_LP decreased with increasing MC in all orthotropic directions, whereas the individual decline in T_LP was affected differently by MC. In the β-relaxation process, the T_LP was more sensitive to MC changes in the L direction than in the transverse directions. In addition, the individual T_LP in the R and T directions was influenced by per unit adsorbed water to a similar degree for the β and γ-relaxation processes. These findings suggest that the difference in the orthotropic viscoelastic performance might cause some drying defects during the water loss process.     

PT/BADCy/PASF三元树脂体系耐热性能的研究

首先研究了PT/BADCy二元树脂体系的力学性能和耐热性能,结果表明：BADCy的加入可以改善PT树脂韧性,体系中PT树脂比例越高,灼烧后混合树脂的残留率越高.还重点研究了PT/BADCy/PASF三元树脂体系,力学分析表明：PASF的加入,大大提高了体系的韧性,当含量为10％wt时,常温、200℃以及300℃剪切强度分别为20.88、22.78、14.36MPa,90°常温剥离强度为26.89N/cm.热学分析表明：不同含量PASF的三元树脂体系的热降解趋势基本一致,高温灼烧后残留率大致相同.PASF树脂的耐热性、耐灼烧型与PT/BADCy相当,三者可以实现理想匹配.     

甲醛低聚反应研究

以甲缩醛为原料合成聚缩醛二甲醚,考察了催化剂、反应温度、物料配比、反应时『司、搅拌转速等因素对反应的影响。结果表明：以树脂为催化剂,催化剂用量5、vt％左右,甲醛和甲缩醛的摩尔比为1．0～1．5：1,反应温度96～105℃,搅拌转速为600～800r／min,通入的N2初始压力0．8～1．0MPa。在此条件下反应4～6h,反应转化率达到65％左右,选择性为90％左右。