NaOH and Ba(OH)_2 Compound Catalyzed PhenolResorcinol-Formaldehyde Copolycondensation Resin Adhesive for Recombined Bamboo

In order to reduce the curing temperature, shorten the curing time of phenol-formaldehyde(PF) resin adhesive, and ensure the good water-solubility, NaOH and Ba(OH)_2 were used as compound catalysts. The influences of the adding time of Ba(OH)_2, the adding amount of NaOH, Ba(OH)_2 and resorcinol on the properties of adhesives were studied. The properties of NaOH catalyzed phenol-formaldehyde(PF) adhesive, NaOH and Ba(OH)_2 compound catalyzed PF adhesive, NaOH and Ba(OH)_2 compound catalyzed phenol-resorcinol-formaldehyde(PRF) adhesive, and the prepared recombinant bamboo with three kinds of adhesives were compared. The experimental results show that NaOH and Ba(OH)_2 compound catalyst not only shortens the curing time of PF adhesive, but also guarantees the suitable water solubility of adhesive. After copolycondensation with resorcinol, the curing time of adhesive is further shortened, the water solubility is improved obviously, and the highest bonding strength is obtained. Infrared spectrum analysis shows that the reaction activity point of NaOH and Ba(OH)_2 compound catalyzed PRF adhesive will increase, so that both the curing temperature and curing enthalpy decrease.

STUDIES ON THE ADSORPTION OF PHENOLIC COMPOUNDS ON A PS-BASED RESIN MODIFIED BY NITRO FUNCTIONAL GROUPS

A new adsorbent (JN-01) was prepared by modifying resin NDA-1800 with nitro functional groups.The adsorption capacities of resins XAD-4,NDA-1800 and JN-01 were investigated,and the results indicated that the modified resin JN-01 was much better in adsorbing phenol,p-nitrophenol and p-cresol.The adsorption capacities of the resin JN-01 were higher than those of the resins XAD-4 and NDA-1800 within a temperature range of 283-323 K,which might be attributed to the higher surface area and the partial polarity o...

THERMODYNAMIC STUDY OF ADSORPTION OF PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTION BY A WATER-COMPATIBLE HYPERCROSSLINKED POLYMERIC ADSORBENT

Equilibrium data for the adsorption of phenolic compounds, i.e., phenol, p-cresol, p-chlorophenol and p- nitrophenol from aqueous solutions by a water-compatible hypercrosslinked polymeric adsorbent (NJ-8) within temperature range of 283-323 K were obtained and correlated with a Freundlich-type of isotherm equation, so that equilibrium constants KF and n were obtained. The capacities of equilibrium adsorption for all the four phenolic compounds on the NJ-8 from aqueous solutions are around 2 times as high as those of Amberlite XAD-4, which may be attributed to the unusual micropore structure and the partial polarity on the network. The values of the enthalpy (always negative) are indicative of an exothermic process, which manifests the adsorption of all the four phenolic compounds on the two polymeric adsorbents to be a process of physical adsorption. The negative values of free energy change show that the solute is more concentrated on the adsorbent than in the bulk solution. The absolute free energy values of adsorption for NJ-8 are always higher than those for Amberlite XAD-4, which indicates that phenolic compounds are preferentially adsorbed on NJ-8. The negative values of the adsorption entropy are consistent with the restricted mobilities of adsorbed molecules of phenolic compounds as compared with the molecules in solution. The adsorption entropy values of phenolic compounds for NJ-8 are lower than those for Amberlite XAD-4, which means the micropores of NJ-8 require more orderly arranged adsorbate.

Adsorption/desorption of toluene on a hypercrosslinked polymeric resin in a highly humid gas stream

In many sources of volatile organic compounds (VOCs), large amounts of water vapor come from the air and the reactors. The relative humidity (RH) of exhaust gas is normally >60% and is supersaturated. Maintaining the property of adsorbent on VOCs in a highly humid gas stream is a serious industrial problem. In this study, the adsorption/desorption behavior of toluene in a micro-mesoporous polymeric resin was investigated in a highly humid environment to explore the influence of abound water vapor on resin adsorption and regeneration. This resin could selectively adsorb toluene at an RH of 80%, and its adsorption property was unaffected by the presence of water vapor. In the case of humidity saturation, the resin displayed a high adsorption capacity at a moisture content of <30%. Therefore, the polymer resin is an excellent water-resistant adsorbent of VOCs. In the regenerative experiment, the resin maintained its original adsorption capability after four adsorption/ desorption cycles of toluene purging with nitrogen gas at 120℃. The resin exhibited excellent regeneration performance at high humidity.

耐磨环氧树脂团状模塑料的制备与性能研究

本文以环氧树脂为基体,将其与短切玻璃纤维、硫酸钙晶须混合制备环氧树脂团状模塑料(EP-BMC),经过模压固化成型,研究玻纤填料比对EP-BMC材料耐磨性、力学性能、尺寸稳定性的影响。结果表明:随着玻纤填料比增加,EP-BMC材料热老化后的耐磨性能、线膨胀系数持续减小,拉伸强度和弯曲强度均呈现先增大后减小的趋势。当玻纤与填料质量比为30∶40时,EP-BMC材料的综合性能最优,热老化后体积磨损为1.00 mm^(3),拉伸强度和弯曲强度分别为56 MPa和145 MPa,线膨胀系数为24.94μm·m^(-1)·℃^(-1),体积电阻达到2.0×10^(13)Ω。

有机硅改性酚醛树脂复合材料制备及性能研究

本文开展了有机硅改性酚醛树脂复合材料制备及性能研究。首先进行有机硅改性酚醛树脂复合材料的制备:将4 g甲基苯基二甲氧基硅烷溶于25 m L四甲基氢氧化铵中,然后将得到的料液添至去离子水中进行搅拌,得到黄色固体,并将其置于60℃烘箱中,设置时间24 h,得出有机硅改性酚醛树脂复合材料。再者,对有机硅改性酚醛树脂复合材料的热性能及复合材料层间剪切强度进行测试。研究结果表明:当固化环氧树脂和固化剂质量比为95∶5时,有机硅改性酚醛树脂复合材料性能最优,此时其层间剪切强度高达87.5 MPa,热失重质量为0.22 g,耐热性能更好。

Rapid, Semi-Automated Fractionation of Freshwater Dissolved Organic Carbon Using DAX 8 (XAD 8) and XAD 4 Resins in Tandem

Natural dissolved organic carbon (DOC) consists of different bio-molecular classes of compounds that are currently very difficult and time-consuming to isolate as individual compounds. However, it is possible to separate natural DOC into hydrophobic and hydrophilic fractions. Such characterisation approaches are becoming increasingly important because, over the past 20 years natural DOC concentrations have been rising rapidly in many parts of the world, most likely influenced by climate change. Higher DOC concentrations in drinking water catchments present a serious problem for the water industry because DOC can form disinfection by-products DBPs during water treatment (e.g. chlorination). Hence, there is an urgent need to better characterise natural DOC before, during and after water treatment. However, current DOC fractionation procedures are extremely laborious requiring days and continual manual monitoring to separate sufficient quantities of DOC for subsequent analysis. This seriously limits sample throughput and the parameter space which can be studied. In this paper, we propose a much more rapid semi-automated method (12.5 hours/litre/sample) which utilises readily available equipment, i.e., HPLC pump or similar and sequential columns of Amberlite DAX 8 and XAD 4 resins. The method reduces the manual input from continual attention to minutes. This paper describes the development of the method and its application in the fractionation of natural DOC from reservoir and lake samples fed from upland peat-land catchments. Recoveries are found to be comparable to those using the manual technique, with the dominant component being hydrophobic acid accounting for 35% - 40% of the natural DOC with the second largest, being hydrophilic acid at 20% - 27%.

苯酚-甲醛树脂MK-95在轿车子午线轮胎胎体胶中的应用

研究苯酚-甲醛树脂MK-95(简称MK-95)在轿车子午线轮胎胎体胶中的应用。结果表明:MK-95不含游离间苯二酚和其他添加剂,其软化点和挥发分含量低于间苯二酚-甲醛树脂;在胎体胶中以MK-95等量替代间苯二酚-甲醛树脂,胶料的硫化特性、物理性能、动态力学性能和粘合性能相当,成品轮胎的高速、耐久和路试性能均达到要求。

新型有机硼防污剂在自抛光防污涂料中的匹配稳定性和防污性能研究

本工作探究了一种新型有机硼防污剂——4-异丙基吡啶甲基二苯基硼烷(4-IPDMB)在防污涂料中的稳定性和防污性能。以稳定水解的丙烯酸硅树脂为自抛光基体树脂,以4-IPDMB为主防污剂,以吡啶硫酮锌、溴代吡咯腈或异噻唑啉酮等作为辅助防污剂,制备了多种防污涂料,并进行性能表征。首先采用一步自由基聚合法成功制备了一种具有稳定抛光速率的丙烯酸硅树脂,抛光速率测试结果表明该丙烯酸硅树脂的抛光速率为4μm/month。按配方将如上组分配制成涂料后,通过附着力试验、储存稳定性试验和浅海静态挂板试验对4-IPDMB在防污涂料中的配方匹配稳定性和防污能力进行了表征。结果表明,含有4-IPDMB的防污涂料具有良好的防污性能,当与其他辅助防污剂混合后,附着力、防污性能和储存稳定性均产生一定程度的变化,需进一步探究4-IPDMB与辅助防污剂之间的潜在化学反应,指导配方优化。

三聚氰胺固废改性酚醛树脂的合成及其对模塑料性能的影响

固体废弃物的绿色化处置与传统材料的资源化改性对当前化工与材料类产业的健康发展具有重要的意义。本文采用固体废弃物OAT(oxiaminothriazine)对酚醛树脂进行改性,探讨了OAT反应性引入酚醛树脂的可行性,以获得的改性树脂作为基体制备了酚醛模塑料,探讨了改性树脂对模塑料性能的影响。结果显示:OAT与甲醛具有一定的反应性,OAT的引入使酚醛树脂的黏度有所下降,但随着用量的进一步增加,黏度增加,聚合速度加快,流动度显著降低,OAT的用量在8%左右为宜;采用OAT改性酚醛树脂制备的模塑料具有较好的热稳定性和电气强度,其他性能与普通模塑料相当。

铁路钢桁梁桥明桥面复合轨枕宏-细观力学行为研究

复合轨枕是明桥面结构提质改造的重要举施,但复合成型工艺及材料特性对轨枕服役性能有直接影响。针对复合轨枕明桥面结构的特性,基于ABAQUS等仿真平台,分别建立复合轨枕的宏、细观有限元模型,从多尺度仿真角度研究列车轮载下复合材料密度,纤维束直径、取向和分布等因素对轨枕承载能力及变形影响。结果表明:增大纤维束直径、使纤维束充分分散,能够减少10%~30%的轨枕受力;改变纤维取向对提高轨枕承载力的效果较为显著,优化纤维分布取向能够使轨枕表面受力减小20%~30%;在此基础上提出“45°/0°/45°”的纤维束铺层结构,采用这种结构能在相同变形量控制水平下获得更高的承载能力,较全断面纵向铺层方案提升30%~50%。研究表明:利用复合轨枕的材料特性,优化生产制造工艺可提高其承载能力。

腰果酚改性酚醛树脂的合成及其模塑料的性能

资源化、环保化与低成本化是传统材料的重要发展方向,本文在硼酸的辅助下,采用腰果酚对酚醛树脂进行改性,探讨了腰果酚和硼酸的引入及其用量对树脂性能的影响,以改性树脂为基体制备了酚醛模塑料,并对其性能进行的测试。结果显示:腰果酚的引入和用量会显著影响树脂的性能,高的替代量使树脂软化点和热稳定性下降,在硼酸的辅助下,则能够实现对改性树脂性能的有效调控,并且以该改性树脂制备的模塑料显示出较好的韧性和热稳定性。

DOPS/TPT复配阻燃环氧树脂的性能

单一的磷杂菲或三嗪类阻燃剂的阻燃效果有限,为了提高阻燃剂在环氧树脂(EP)中的阻燃效率,将9,10-二氢-9-氧杂-10-磷杂菲-10-硫化物(DOPS)与2,4,6-三苯氧基-1,3,5-三嗪(TPT)复配应用于EP中,通过协同阻燃作用来提高EP的阻燃性能,以期获得优异的阻燃效果。文中将DOPS与TPT进行复配,采用熔融共混法制备了阻燃EP复合材料。通过热重分析、垂直燃烧、极限氧指数、锥形量热和力学性能测试研究了复合阻燃剂DOPS/TPT对阻燃EP复合材料的热稳定性、阻燃性能及力学性能的影响,并采用扫描电镜、热重-红外光谱联用分析了材料的残炭形貌和热解气体,探究了其阻燃机理。结果表明,当阻燃剂的总添加量为9%,DOPS在复合阻燃剂DOPS/TPT中的质量分数为8%时,复合材料EP/DOPS/TPT的LOI值为30.5%,达到UL-94 V-0级,而且其平均热释放速率(av-HRR)、总热释放量(THR)值最低,其阻燃性能、成炭性能和力学性能均优于单独添加DOPS或TPT。从阻燃机理看,2种阻燃剂在气相和凝聚相发挥了协效阻燃作用,弥补了单一阻燃剂的不足,能够进一步提高阻燃效果。

抗撕裂树脂AD-1600在矿用全钢子午线轮胎胎面胶中的应用

研究抗撕裂树脂AD-1600在矿用全钢子午线轮胎胎面胶中的应用。结果表明:随着抗撕裂树脂AD-1600用量的增大,胶料的t90延长,定伸应力和拉伸强度略降低,拉断伸长率先提高后降低,抗撕裂性能和抗切割性能显著提高;当抗撕裂树脂AD-1600用量为6份时,胶料的抗撕裂性能和抗切割性能最佳,且生热较低。

聚氨酯复合材料耐盐雾力学性能研究

在严格的环保政策下,乙烯基树脂复合材料的制作受到环保的制约。以聚氨酯为基体的复合材料体现出其独特的的优势,其施工环境得到有效的改善,无溶剂型聚氨酯树脂,无刺激性气味,大大减少了对环境和工人健康的影响。本文对环保型聚氨酯树脂和乙烯基树脂在相同盐雾实验条件下的力学性能进行实验测试数据对比。结果表明:乙烯基树脂和聚氨酯复合材料在相同盐雾实验条件下拉伸强度和弯曲强度未发生较大变化,两种复合材料耐盐雾性较好。

电动汽车功率电子封装用耐高温环氧塑封料的研究进展

本文综述了近年来国内外关于耐高温环氧塑封料(EMC)的基础研究与应用进展,从先进功率电子器件发展对塑封材料的性能需求、传统EMC的高温降解机理、EMC结构与耐热稳定性的关系以及提高EMC耐热稳定性的改性途径等方面进行了阐述。重点综述了多芳环(MAR)型以及含萘型EMC的发展状况。最后对功率电子封装用耐高温EMC未来的发展趋势进行了展望。

一种含笼状硫代磷酸酯仲胺盐的合成与应用

不饱和聚酯树脂(UPR)具有优异的工艺性能和较好的拉伸强度等,因此其用途较为广泛,但UPR在燃烧时会产生大量的黑烟,会严重影响人的生命健康安全。为提升UPR的阻燃性能以及热稳定性,采用以三氯硫磷(PSCl3)、季戊四醇、马来酸酐(MA)和哌嗪为原料,合成一种含有含氮、磷、硫三种阻燃元素的协同阻燃剂,并在该阻燃剂分子中引入笼状结构,以提升UPR热稳定性、力学性能以及阻燃性能等。采用傅里叶变换红外光谱、核磁共振氢谱、热重分析等表征方式对合成目标产物进行了结构和热稳定性鉴定。同时,对所合成的最终产物含笼状硫代磷酸酯仲胺盐(PI-MA-SPEPA)的工艺条件进行了优化,探讨了溶剂配比、反应时间、反应温度等对合成产物产率的影响。研究表明反应温度30℃,反应时间4 h,乙醇和水的最佳溶剂配比为1∶1,最终产物的反应产率最高,可达82.9%。最后,通过垂直燃烧测试对添加阻燃剂的UPR进行了阻燃性能的评价。结果表明,在UPR中加入18%的PI-MA-SPEPA,UPR的阻燃性可达到V-0级。

环氧-酚醛-双马来酰亚胺三元共混物的制备及性能研究

采用4,4′-二苯甲烷双马来酰亚胺(BMI)与多芳环型酚醛树脂、多芳环型环氧树脂(NC3000)及促进剂2-苯基-4-甲基-5-羟甲基咪唑(2P4 MHZ)熔融共混,制备了三元树脂共混物(BPE)及其固化产物,并对其性能进行了评价。研究结果表明:BPE三元树脂共混物仅出现了一种固化行为,在现有环氧塑封料(EMC)制备工艺中可固化完全;结构特征分析表明,成功制备了BPE三元树脂共混物,并且三元树脂之间发生了相互交联反应;三元树脂共混物的结晶状态及流变学分析表明,三元共混物呈现出明显的非晶特性,随着温度的升高,熔体黏度均开始下降,在140~160℃时达到最低值,然后随着凝胶化会迅速增加几个数量级,并且在110~160℃内存在一定的加工窗口,对EMC的制备是有利的;随着BMI含量的增加,三元树脂固化物的耐热稳定性也在不断增加,10%的热分解温度均超过430℃;此外,BMI引入也使得共混物凝胶时间延长,并且破坏了环氧/酚醛树脂体系的固化交联,导致高温热老化失重的增多。

活性炭和树脂吸附去除水中PFAS的研究进展

全氟或多氟烷基化合物(PFAS)具有持久性、生物累积性和潜在生物毒性,在水环境中被广泛检出。吸附作为有效的PFAS处理技术具有低成本、易操作等优点。活性炭和树脂是较为常用的PFAS吸附剂。总结了活性炭和树脂改性前后对PFAS的吸附性能,介绍了其吸附机理。结合目前吸附去除水环境中PFAS的研究进展,展望了吸附法用于水中PFAS处理的发展方向,为进一步开发高效、实用的PFAS吸附去除技术提供参考。

基础聚合物对硅烷改性聚醚密封胶性能的影响

以不同模量的4种硅烷改性聚醚 (MS )树脂为基础聚合物,添加增塑剂、补强填料、抗氧剂、除水剂、硅烷偶联剂、催化剂等制得单组分MS密封胶,研究了基础聚合物种类对MS密封胶性能的影响。结果表明,采用40份MS树脂3368T与50份MS树脂Sax750复配作为基础聚合物时,制得的MS密封胶性能较佳,外观无明显颗粒,表干时间为13 min,稠度为7.5 cm,24 h固化深度为4 mm,拉伸强度为 2.1 MPa ,拉断伸长率为706%,邵氏A硬度为46,拉伸模量为1.62 MPa,剪切强度为2.2 MPa,剪切模量为0.35 MPa。