尿素—苯酚—甲醛树脂胶粘剂的研制

本文研究了由苯酚、甲醛和尿素为主要原料制备尿素－苯酚－甲醛（简写为ＵＰＦ）树脂胶粘剂的配比及工艺条件。制得的胶粘剂的游离酚、游离醛含量低，水溶性、贮存性好，原料成本低，适用于浸渍作保温材料的矿物纤维。     

尿素改性苯酚-甲醛树脂胶粘剂的研究

研究了由苯酚、甲醛和尿素为主要原料制备尿素－苯酚－甲醛（简写为ＵＰＦ）树脂胶粘剂的配比及工艺条件。制得的胶粘剂的游离酚、游离醛含量低,水溶性、贮存性好,原料成本低,适用于浸渍作保温材料的矿物纤维。     

改性聚乙烯醇甲醛胶粘剂的研制

介绍了以聚乙烯醇、甲醛、淀粉等为主要原料制备聚乙烯醇缩甲醛胶粘剂的工艺。探讨了甲醛、淀粉、尿素和改性剂的用量、pH值、反应温度等因素对聚乙烯醇缩甲醛胶粘剂的制备与性能的影响。实验结果表明，制备聚乙烯醇缩甲醛的优化配方及工艺条件为：聚乙烯醇26．2g、甲醛 4g、淀粉5．4g、尿素3g、改性剂3g、水120g，pH值为2－3，反应温度80－85℃。制得的聚乙烯醇缩甲醛胶粘剂具有粘度大、初粘性好、干燥速度快、稳定性好及游离甲醛含量低等优点，是一种良好的啤酒瓶贴标用胶粘剂。     

低游离甲醛脲醛树脂胶粘剂的研究进展

综述了低游离甲醛脲醛胶粘剂的制备技术开发进展,包括降低原料甲醛与尿素物质的量比、采用三聚氰胺、聚乙烯醇、苯酚中的1种或2种改性、控制缩聚条件、加入甲醛捕捉剂等方法.     

苯酚-尿素-甲醛三元共缩聚树脂合成工艺的研究

针对脲醛树脂在制板过程以及人造板材在使用过程中不断释放甲醛。危害人体健康的环保问题,以及耐水、耐老化性能差的缺点。以苯酚、尿素和甲醛为原料,采用高温（90℃）缩聚反应合成苯酚-尿素-甲醛共缩聚树脂（PUF胶黏剂）,缩短了反应时间,提高了耐水、耐老化性能,且游离甲醛含量〈O．3％,游离苯酚含量〈0．5％。对树脂的结构和性能进行全面的分析,得出当甲醛、尿素、苯酚摩尔比为10：8：1时树脂性能最佳,压制的胶合板力学性能好,板材甲醛释放量达到GB18580—2001中E2级水平。     

低毒稳定型脲醛树脂胶粘剂的制备

在尿素与甲醛加成－缩合反应中,分２次加入自制ＰＱ复合添加剂,可明显降低游离甲醛的含量,提高脲醛树脂胶粘剂的稳定性。添加剂的最佳用量为ＵＦ胶总量的１．０％－１．４％。     

低游离甲醛脲醛树脂胶粘剂的研制

尿醛树脂胶粘剂中的游离甲醛是人造板中主要的污染源。采用降低原料中甲醛和尿素摩尔比 ,分批加入尿素进行多次缩聚的方法降低游离甲醛的含量 ,并通过添加聚乙烯醇改性剂 ,使产品中游离甲醛的含量为 0 4 % ,产品陈放 1周后 ,游离甲醛降到 0 1%以下 ,完全可以满足环境保护的要求。该制备工艺简单 ,成本低     

苯酚/甘脲改性脲醛树脂胶黏剂的制备及性能研究

以尿素和甲醛为原料、苯酚/甘脲为甲醛捕收剂制备脲醛树脂(UF)。增加苯酚/甘脲用量,脲醛树脂中游离甲醛的质量分数降低,固化时间增加。增加缩聚时间,脲醛树脂的黏度增加,游离甲醛的质量分数降低。研究结果表明,当苯酚质量分数为0.5%、甘脲质量分数为0.5%、三聚氰胺质量分数为1%、缩聚时间为20 min时,采用一次性加入甲醛、分批次加入尿素和改性剂的碱-酸-碱合成工艺制备的UF中的游离甲醛的质量分数约为0.042 6%,远低于浙江DB33-T-494的E1级指标。     

环保型脲醛树脂胶粘剂的合成

根据尿素与甲醛加成一缩合反应机理，利用强酸催化工艺合成低甲醛含量的脲醛树脂胶粘剂，并对主要反应条件：pH值，尿素的投放次数及反应温度对胶粘剂游离甲醛的影响进行了探讨。制得环保型脲醛树脂胶粘剂。     

苯酚处理液体木质素改性酚醛树脂胶粘剂的制备及性能表征

在碱性条件下,液体木质素先经苯酚处理后替代部分苯酚对酚醛树脂进行改性,制备得到液体木质素改性酚醛树脂(LPF)胶粘剂。考察了催化剂用量(苯酚处理木质素时氢氧化钠用量)、苯酚与甲醛(P/F)的物质的量之比、聚合温度、聚合时间对LPF胶粘剂性能的影响。研究结果表明:当催化剂用量3%、n(苯酚)∶n(甲醛)=1∶1.975、聚合温度90℃、聚合时间50 min时,所制备的LPF胶粘剂的干湿胶合强度分别为3.15、1.46 MPa,较未经改性的PF胶粘剂分别提高了17.5%、8.1%,游离苯酚的含量降低至0.62%;LPF胶粘剂的游离甲醛含量为0.22%,固体含量为52.8%,黏度为125 mPa·s。红外分析结果表明,苯酚处理后的木质素可以代替苯酚与甲醛发生反应生成新的物质,该物质有可能与PF胶粘剂发生接枝共聚产生新的醚键桥接,由此也说明在制备LPF胶粘剂过程中木质素发生了化学反应。     

COPNA树脂的合成及其复合材料耐热性

以三种不同的油浆为原料,在酸性催化剂存在下,与对苯二甲醇反应,得到三种COPNA树脂。以COPNA树脂、酚醛、环氧树脂为基体,与碳纤维复合,通过模压成型,得到三种不同基体的复合材料。考察了COPNA树脂的软化点、残炭、β树脂含量等粘结性参数以及树脂/炭纤维复合材料的耐热性能。经过分析认为,得到的COPNA树脂可以达到工业粘合剂的要求,具有很好的粘绪作用;以COPNA树脂为基体的炭纤维复合材料,表现出很好的耐热性,这为COPNA树脂的应用提供了一个很好的方向。     

耐热性汽车制动材料的研究

围绕耐热性汽车制动材料的研制，用索氏抽提法测定了双酚Ａ型苯并恶嗪中间体在路易斯酸和六次甲基四胺作用下树脂的固化程度，同时利用ＩＲ、ＤＴＡ、ＴＧＡ等测试方法研究了固化物的结构和热稳定性。制备了以该树脂为基体的制动材料，测定了制动材料的热膨胀性及摩擦磨损性能，结果表明，开环聚合酚醛树脂具有良好的热稳定性，其制动材料高温摩擦系数稳定，热恢复性良好，热膨胀小。     

Synthesis and Characterizations of Melamine-Based Epoxy Resins

A new, easy and cost-effective synthetic procedure for the preparation of thermosetting melamine-based epoxy resins is reported. By this innovative synthetic method, different kinds of resins can be obtained just by mixing the reagents in the presence of a catalyst without solvent and with mild curing conditions. Two types of resins were synthesized using melamine and a glycidyl derivative (resins I) or by adding a silane derivative (resin II). The resins were characterized by means of chemical-physical and thermal techniques. Experimental results show that all the prepared resins have a good thermal stability, but differ for their mechanical properties: resin I exhibits remarkable stiffness with a storage modulus value up to 830 MPa at room temperature, while lower storage moduli were found for resin II, indicating that the presence of silane groups could enhance the flexibility of these materials. The resins show a pot life higher than 30 min, which makes these resins good candidates for practical applications. The functionalization with silane terminations can be exploited in the formulation of hybrid organic-inorganic composite materials.     

环氧乙烯基酯树脂及层合板的耐碱性能

对双酚A型环氧乙烯基酯树脂及应用于各种纤维增强层合板的耐碱性进行了分析,认为:要提高纤维增强复合材料的耐碱性,需选择耐碱性较好并能与纤维良好浸润的乙烯基树脂,选择锦纶等耐碱性较好的有机纤维。     

The effect of grain shape on the properties of PVC resins and compounds

The properties of PVC resin grains have been shown to influence the bulk density and flow properties of PVC resins and powder compounds. Bulk densities of PVC resins and powder compounds are highly dependent on grain shape. Lower bulk density has been related to more irregular grain shape. Flow properties of PVC resins and powder compounds improve with increased grain size. Twin screw extrusion rates are directly proportional to the compound bulk density in the feed throat.     

Recent developments in the chemistry of cyanate esters †

During the last decade, aromatic cyanate esters (CE) have become established as a new and unique class of high-performance thermosetting resins for use as prepreg matrices in both the electronic and aerospace industries. The basic properties of CE resins, such as low moisture absorption, excellent electrical properties and good flammability characteristics, make them attractive composite matrices and differentiate them from standard epoxy resins (epoxies) and bismaleimides. Although they are relative newcomers to the composites industry, CE resins are enjoying unprecedented success for certain applications. Several major space and radome manufacturers have qualified CE resins despite the extensive database on epoxies and the inherently conservative nature of industry. Increasing demands on the materials used in these areas have stimulated the use of CE resins over other more conventional polymers. The aim of this review is to bring to the reader's attention the more recent developments in the science of cyanate esters. © 1998 Society of Chemical Industry     

Development of metal-bonding spray adhesives for use in aerospace repair applications

In many aerospace applications, the use of film and paste adhesive materials is not conducive to either good manufacturability or good bonding properties. To address this concern, the development of high-performance, epoxy-based, spray-adhesive resins has been undertaken from a research and development standpoint. These materials were investigated in the light of their potential repair applications, with focus on adhesive joint designs based on lap-shear performance and processibility of the adhesive. It was found that the resins investigated displayed adequate lap-shear strengths for the bond types of interest. However, some resins proved to be a considerable challenge during processing and solvent removal presented a problem for some materials. As expected, the combined use of mechanical testing and scanning electron microscopy revealed that the lap-shear strengths of the resins could be tailored with changes in their chemistry, and that these changes also affected the solvent removal process.     

Toughening of AT-Resins with a Polyphenylquinoxaline

Acetylene terminated (AT) resins are addition-curable thermoset materials which do not generate volatiles during cure and therefore can be fabricated into void-free structures. They retain good thermal and mechanical properties even after exposure to high humidity environments. Their use as composite matrix resins and adhesives has shown promise. These resins, however, are brittle. Molecular structure modifications and blending with thermoplastic modifiers have been used to improve their toughness. In this work, improvement in toughness has been sought through the use of a polyphenylquinoxaline (PPQ) modifier. The blended systems showed improvements in toughness, thermooxidative stability, and lap shear strength over the original AT-resins.     

Synthesis, characterization, and analyses of mechanical, adhesion, and thermal properties of polysiloxane resin modified with segmented polyurethane

Novel heat-resistant coating materials with excellent adhesion properties were prepared by modification of polysiloxane resin (PSil) with a pre-synthesized tailored polyurethane/polyurea copolymer end-capped with siloxane (PU). The modification was achieved by crosslinking the hydroxyl group of PSil and ethoxy group of PU in the presence of di-n-butyltin dilaurate. The chemical structure of PU was analyzed by Fourier Transform Infrared and Hydrogen-1 Nuclear Magnetic Resonance spectroscopic methods. A series of modified silicone resins (MSRs) have been synthesized and investigated. The molecular weights of the resins were determined by means of gel permeation chromatography. The morphology of the MSR studied by scanning electron microscopy has shown that the resin containing 30% of PU has a small particle size and a good particle size distribution. The adhesion and the mechanical properties of the resins containing 20, 30, and 40% of PU have shown a good performance. Using thermogravimetric analysis, the thermal properties and the thermal degradation of the MSR were investigated.