脲醛树脂的研究进展

综述了近年来脲醛树脂的研究进展,从低甲醛脲醛树脂的合成工艺研究、改性脲醛树脂的合成工艺研究、环保脲醛树脂的合成工艺研究等方面进行了归纳和评述,展望了脲醛树脂未来的研究方向和发展前景。     

化工实用技术资料

053 低毒脲醛树脂的合成机理 应用胶体理论,在不脱水、不增加过多改性剂的基础上,探索了低毒脲醛树脂胶的合成机理。所得胶达到GB/T14372-93要求,制得的刨花板满足GB/T4897-92A类板一等品要求,甲醛释放量达到欧洲En级。 054 改性脲醛树脂胶粘剂的研制 利用聚乙烯醇缩甲醛树脂在酸性条件下与大分子脲醛树脂进一步交联,合成了改性脲醛树脂胶粘剂。分步加入尿素,降低了脲醛树脂中的游离甲醛含量,提出了工艺条件及影响合成的因素。 055 脲醛树脂低醛胶制备工艺进展 提出了脲醛树脂胶粘剂的低醛化控制理论。认为提高树腐化反应平衡常数是最理想的控制手段,也是脲醛胶生产工艺改进的方向。 056 低游离甲醛含量脲醛树脂胶粘剂的合成     

苯酚改性脲醛树脂泡沫耐水性的研究

研究了用苯酚改性脲醛树脂发泡的合成工艺。探讨了甲醛、尿素和苯酚的摩尔比脲醛树脂胶黏剂运动黏度的影响,比较了改性前后脲醛树脂泡沫吸水率的变化。结果表明:甲醛与尿素的摩尔比为1.4∶1,苯酚量为尿素的3%时,制得的脲醛树脂的性能良好,符合脲醛树脂的国家标准GB/T14732-2006要求。发泡后的脲醛树脂泡沫耐水性提高。     

木材用脲醛树脂胶粘剂研究进展

介绍了脲醛树脂的形成机理,综述了木材用脲醛树脂胶粘剂的研究进展和工艺的影响因素,提出环境友好型脲醛树脂胶粘剂是未来发展趋势。     

化工实用技术资料

063 低毒脲醛树脂的合成机理 应用胶体理论,在不脱水、不增加过多改性剂的基础上,探索了低毒脲醛树脂胶的合成机理。所得胶达到GB/T14372-93要求,制得的刨花板满足CB/T4897-92A类板一等品要求,甲醛释放量达到欧洲En级。 054 改性脲醛树脂胶粘剂的研制 利用聚乙烯醇缩甲醛树脂在酸性条件下与大分子脲醛树脂进一步交联,合成了改性脲醛树脂胶粘剂。分步加入尿素,降低了脲醛树脂中的游离甲醛含量,提出了工艺条件及影响合成的因素。 055 脲醛树脂低醛胶制备工艺进展 提出了脲醛树脂胶粘剂的低醛化控制理论。认为提高树脂化反应平衡常数是最理想的控制手段,也是脲醛胶生产工艺改进的方向。 056 低游离甲醛含量脲醛树脂胶粘剂的合成     

苯酚改性脲醛树脂

本文探讨了苯酚改性脲醛树脂的合成工艺及应用,并对苯酚改性脲醛树脂竹材复合板与普通脲醛树脂竹材复合板的性能进行了对比。     

《脲醛树脂胶黏剂——制备、配方、分析与应用》简介

本书对脲醛树脂的合成方法，原料质量及检测方法，脲醛树脂生产设备、配方、制备工艺、分析检验方法均做了较为详细的介绍。重点介绍了降低脲醛树脂中游离甲醛、控制人造板甲醛释放量的方法，以及脲醛树脂在人造板工业中的应用。对脲醛树脂在包装、涂料、模塑粉、纸张、皮革等领域的应用也作了简要介绍。     

低摩尔比脲醛树脂胶粘剂研究进展

从脲醛树脂胶粘剂的游离甲醛含量及其胶接制品的甲醛释放量,低摩尔比脲醛树脂的合成及不同固化体系下低摩尔比脲醛树脂的固化特性等方面,综述了近几年来低摩尔比脲醛树脂作为木材胶粘剂的研究进展。     

化工实用技术资料

053 低毒脲醛树脂的合成机理 应用胶体理论,在不脱水、不增加过多改性剂的基础上,探索了低毒脲醛树脂胶的合成机理。所得胶达到GB/T14372-93要求,制得的刨花板满足GB/T4897-92A类板一等品要求,甲醛释放量达到欧洲En级。 054 改性脲醛树脂胶粘剂的研制 利用聚乙烯醇缩甲醛树脂在酸性条件下与大分子脲醛树脂进一步交联,合成了改性脲醛树脂胶粘剂。分步加入尿素,降低了脲醛树脂中的游离甲醛含量,提出了工艺条件及影响合成的因素。     

我国低毒脲醛树脂研究进展

综述了国内低毒脲醛树脂研究进展,着重介绍了控制脲醛树脂中甲醛释放量的方法,包括脲醛树脂合成工艺的研究,降低羟甲基、亚甲基醚、半缩甲醛的分解,固化过程中所释放游离甲醛的捕捉,以及脲醛树脂改性。     

Dispersed Resin in Bleached Kraft Pulp Mills

Abstract

Several properties of the dispersed resin in bleached kraft pulp mills have been investigated. Average concentrations of resin particles in filtrates of pulps from various points along the process stream are reported. For each sampling location, the change in particle concentration with time of pulp sample storage at 5°C has been determined. In the future, this will enable rough estimation of original concentrations when samples must be measured a few days after collection. Size distributions of resin particles were the same at all sampling points, from which it follows that, in practice, the relationship between concentration and deposition rate is relatively unaffected by size distribution. Dispersed resin particles were negatively charged throughout the mills. The low charge observed in C-stage pulps was insufficient to confer stability, which further supports the hypothesis that the dispersed resin is heterocoagulated with the fibers in this acidic stage.     

环保型高固体分醇酸树脂的合成

醇酸树脂在涂料中占有重要的地位,它以其经济,易于施工和与其它树脂易交联的特性以及具有通用性而被广泛应用于涂料工业中,在合成树脂中扮演着重要的角色。随着人们对环境要求的提高,为了减少环境污染,人们开始大力发展"绿色涂料"。提高固体分,降低溶剂的使用是一种较好的方法,通过研究我们得到了符合环保要求的醇酸树脂。     

Prepreg processing science and engineering

Resin flow and fiber spreading during the prepregging process were investigated experimentally using a scale-down version of a commercial hot-melt prepregger with bismaleimides and carbon fibers as model systems. Specifically, several dimensionless parameters such as the Prepreg Flow Number, fractional resin uptake, resin distribution function, fractional width change, and prepregging efficiency were defined to characterize the prepregging process as well as the quality of the prepreg. Fiber spreading during the prepregging process was observed to be a viscoelastic phenomenon depending on the impregnation temperature. For resin impregnation into collimated fiber tows, all the experimental data points obtained at different operating conditions were superimposed onto a single line showing a temperature-pressure-velocity superposition for the prepregging process as predicted by the definition of the Prepreg Flow Number (PFN). Finally, three fundamental steps of the prepregging process were identified and confirmed with cross-sectional micrographs of unaged prepregs produced at different temperatures.     

氟表面活性剂和氟聚合物(IX)——全氟磺酸树脂和全氟磺酸离子交换膜

全氟磺酸树脂(PFAR)及其前体全氟磺酰氟树脂(PFSR),以及由其为基材制备的全氟磺酸离子交换膜(PFSIEM)是重要的氟化工产品,在氯碱工业、燃料电池、化工生产和国防安全等领域有重要应用。介绍了PFSR,PFAR和PFSIEM的发展历程、产品种类、制备方式、加工方法、表征方法和产品应用,并对其研究热点及我国在该领域的发展进行了展望。     

An investigation on the effect of phenylboronic acid on the processibilities and thermal properties of bis-benzoxazine resins

Benzoxazine resins (BZs) as a novel type of phenolic resin are high-performance matrix resin for advanced composites. Yet there still exist some deficiencies when used as ablative material in aerospace applications, such as high curing temperature and poor thermal stability. In the present study, the phenylboronic acid (PBA) modified BZs (PBBZs) exhibiting excellent processibilities and thermal properties were prepared by incorporating PBA into BZ. The viscosity, gel time and curing behaviors were examined to demonstrate that PBBZs possessed better processibilities than the BZ, representing the catalytic effect of PBA in this case. The incorporation of PBA accelerated the ring-opening polymerization of BZ, leading to the lower curing temperature. TGA results reveal that the cured PBBZs exhibit excellent thermal properties, where the char yield at 800 °C (nitrogen atmosphere) reaches 63.7% and is increased by 14.1 percentage points than that of BZ. The formed phenylboronates during curing act as additional cross-linking points and increase the cross-linking density of the cured resin, which results in the enhancement of the glass transition temperature of BZ ranging from 165 °C to 219 °C. This study provides a new vision for the preparation of high-performance matrix resin for ablative materials by introducing aryl-boron backbone.     

MBS树脂的合成及表征

采用适时补皂、种子乳液聚合方法合成粒径大、分布窄的SBR胶乳。该胶乳接枝St—MMA共聚单体合成MBS树脂。研究了SBR粒径大小度其分布、MBS玻璃化转变温度以度其微观形态。实验结果表明，MBS树脂具有两个玻璃化转变温度，分别为MBS树脂的橡胶相和树脂相的玻璃化转变温度。且MBS树脂呈现规整的核壳结构。     

用DEPT135测定酚醛树脂的微细结构和组成

为准确了解线形酚醛树脂的组成和微细结构,利用高分辨率核磁共振技术中近年发展起来的DEPT135测定方法,测定了线形酚醛树脂的有关结构参数:o-o位缩聚百分率、o-p位缩聚百分率、p-p缩聚百分率;参与缩聚反应活性点中o位占据百分率、p占据百分率以及各个活性点参与反应百分率;同核双邻位缩聚值;不同类型酚醛树脂的平均核体数。其中,同核双邻位缩聚值、活性点参与反应百分率及苯酚和间甲酚平均核体数的计算方法是笔者建立的,即:Ro-o=100-Po-p-2Pp-p,其中:Po-p=SⅠ+SSⅡⅡ+SⅢ×100%;Pp-p=SⅠ+SSⅡⅢ+SⅢ×100%。     

氧化石墨烯改性碳纤维复合材料抗冲击行为研究

使用单层纳米氧化石墨烯（NGO）粒子对环氧树脂进行改性处理，采用真空辅助树脂传递模塑成型工艺制备了[±45/0/90]_2S铺层角度下的纯树脂及单层NGO改性碳纤维复合材料（CFRP）层合板。通过落锤冲击试验、超声C扫描检测、冲击后压缩试验等对纯树脂及单层NGO改性CFRP进行实验研究。结果表明，纯树脂及单层NGO改性CFRP在损伤阻抗及损伤容限实验中均存在拐点现象，且拐点出现在相同深度位置，其中纯树脂CFRP拐点位置为0.51 mm，单层NGO改性CFRP拐点位置为0.43 mm；相对于纯树脂CFRP，单层NGO改性CFRP可以显著提高复合材料的抗冲击性能及冲击后的压缩性能；通过对冲击后凹坑深度及凹坑面积进行数据模拟，可以用拟合公式实现对复合材料的损伤预测。     

聚氯乙烯隔板树脂的加工应用

简单介绍了聚氯乙烯隔板树脂的应用、工艺流程、技术要点。     

有机硅改性树脂技术的研究进展

介绍了近几年有机硅对树脂进行化学改性的技术及其研究情况。指出目前有机硅改性树脂的研究重点,并对有机硅改性树脂的发展方向进行了展望。