硬质聚氨酯泡沫塑料表面等离子体改性研究

测试了三种泡沫塑料表面（含脱模剂但经等离子体处理、含脱模剂不经等离子体处理和不含脱模剂不经等离子体处理）与涂层之间的结合力,采用XPS表面分析手段分析了涂层附着力提高的原因。     

聚氨酯改性酚醛树脂的研究

本研究采用化学改性的方法,以聚氨酯弹性体为改性单元,对酚醛树脂进行增韧改性,以期改善其作为树脂磨具粘结剂的使用性能。通过对不同聚氨酯含量的改性酚醛树脂粉的耐热性能、拉伸强度、弯曲强度、硬度、切削性能等进行测定,得到以下实验结果：聚氨酯含量为20％的改性酚醛树脂的拉伸强度比未改性酚醛树脂提高了19％,弯曲强度提高了16％,硬度也提高了一个等级,达到Q级。在改性酚醛树脂作为树脂切割片结合剂的应用研究中,发现以聚氨酯含量为20％的改性酚醛树脂为结合剂的树脂切割片的自锐性得到大幅度提高,切削速度提高了2．7倍．     

有机硅和环氧树脂复合改性聚氨酯涂料的研制

通过单因素实验和正交实验,以涂膜的拉伸强度为依据,确定了用有机硅和环氧树脂复合改性聚氨酯涂料时,制备聚氨酯预聚体的单体甲苯二异氰酸酯(TDI)和聚醚二元醇(DL2000)的恰当配比,有机硅、环氧树脂和增塑剂的恰当添加量.以及恰当的反应时间和反应温度.对复合改性涂膜进行了红外光谱分析和热重分析,对比检测了未改性涂料,有机硅改性涂料、有机硅和环氧树脂复合改性涂料的各方面性能.结果表明,有机硅和环氧树脂复合改性的聚氨酯涂料各方面性能良好,涂膜具有较高的力学强度、良好的附着力、较低的吸水率、较好的热稳定性和耐酸碱性能.     

氟改性和硅改性丙烯酸聚氨酯涂层的制备及环境行为

目的研究氟改性和硅改性丙烯酸聚氨酯涂层在不同环境中的失效行为。方法通过溶液聚合法制备具有一定羟基含量的丙烯酸酯树脂,再将丙烯酸树脂与多异腈酸酯固化剂配合,获得丙烯酸聚氨酯涂层。通过在丙烯酸酯合成中引入含氟丙烯酸酯单体,制得氟改性丙烯酸聚氨酯涂层;通过在固化过程中引入氨基硅油,制得硅改性丙烯酸聚氨酯涂层。利用傅里叶变换红外光谱(FT-IR)分析涂层的化学组成。对涂层试样进行温度环境实验(室温和100,150℃)、湿热环境实验和氙灯老化实验,分析涂层疏水性、光泽度等表面特性的变化。结果氟、硅改性有效提高了涂层的疏水性。未改性、氟改性和硅改性三种涂层在100℃以下的环境中服役时,疏水性和光泽度比较稳定。硅改性涂层在150℃的高温环境中较未改性和氟改性涂层失效慢。湿热环境对三种涂层的接触角和光泽度等性能影响不大。氟改性涂层在氙灯老化环境中的失效程度较另外两种涂层轻。结论氟改性涂层耐光老化性能较好,硅改性涂层耐温性较好。     

马来酸酐聚丁二烯改性聚氨酯涂层的耐水及耐蚀性研究

目的改善聚氨酯涂层的耐水性和耐蚀性等综合性能。方法采用可反应型橡胶马来酸酐聚丁二烯(MAPB)化学改性聚氨酯,并通过红外光谱、接触角、耐水性及电化学阻抗谱等对复合涂层的结构与性能进行表征。结果通过比较分析红外光谱(FT-IR)中改性前后聚氨酯基团对应吸收峰的变化,确定了MAPB成功对聚氨酯进行化学改性。随着马来酸酐丁二烯用量的增加,改性聚氨酯涂料表面疏水性增强,吸水率降低,物理机械性能也得到提高。当加入MAPB含量约为3%～5%时,复合涂层的接触角由75°提高到了95°,吸水率由1.5%降低到最低约0.5%,硬度由3H提高到4H,附着力从4B提高为5B。另外,随着浸泡时间的增加,改性涂层的阻抗值下降的更缓慢,表明MAPB的加入提高了涂层的耐腐蚀性能,尤其是含3%马来酸酐丁二烯改性聚氨酯涂层的耐蚀性表现最优异,这也得到盐雾试验的进一步验证。结论加入约3%的马来酸酐丁二烯改性聚氨酯可大幅降低涂层的吸水率,同时涂层的耐蚀性等综合性能得到改善,这主要归因于可反应基团参与交联提高了涂层的致密度,及其主链烯烃的疏水特性提高了涂层阻隔水和腐蚀介质渗透扩散的能力。     

聚氨酯改性氯磺化聚乙烯防腐涂料研制成功

氯磺化聚乙烯是目前用于制造涂料的合成橡胶（氯丁橡胶、丁苯橡胶、丁晴橡胶、丁基橡胶、聚硫橡胶等）中防腐性能最佳的漆基，其使用寿命是其他防腐涂料的1～3倍，是我国长期发展的一种长效防腐材料。但其最大的缺点就是涂料的固体含量低、光泽差，不符合环境友好型涂料发展的要求。     

双组份改性聚氨酯材料强疏水防腐表面性能研究

以全氟烷基醇(TEOH-10)对二苯基甲烷二异氰酸酯(MDI)进行修饰,通过扩链剂进行封端在聚氨酯侧链同时引入氟碳基团和疏水性基团实现双组份改性异氰酸酯,并通过TEOH-10/MDI的摩尔比控制含氟基团(-CF_2CF_3)的数量,制备改性聚氨酯(FPU-s)。以傅立叶红外光谱、核磁共振谱进行成分分析,扫描电镜观察涂层表面形貌、组织结构,分析微相分离结构的影响因素;随着含氟量增加,水接触角达到123.1°而具有强疏水性。本实验通过新型化学改性的方式制备了高水附着力、强疏水性及低表面性等优良性能的防腐蚀改性聚氨酯材料。     

改性水玻璃砂性能研究

本文对水玻璃改性进行了研究,确定了改性方法及制备工艺,并对改性后的水玻璃砂进行了系统的性能试验,同时,对助粘结剂做了一些探讨。试验表明,改性后的水玻璃砂性能提高,溃散效果显著。     

加热工艺对聚氨酯树脂砂失重率及高温强度的影响

研究了加热温度、加热时间对不同配比聚氨酯树脂砂在加热时的失重率及高温强度的影响,利用扫描电子显微镜观察了不同加热条件下的砂粒形貌.结果表明:当加热温度超过500℃以后,树脂砂失重率显著增加;随加热温度提高,聚氨酯树脂砂的高温抗压强度显著降低,当加热温度达到500℃时,聚氨酯树脂砂的高温强度趋于零;聚氨酯树脂砂的最低再生温度为600℃,与之相应的加热时间不少于20 min;当加热温度为700 ℃时,加热5 min就可以将砂粒表面的树脂膜完全去除.     

Y2O3改性渗铝工艺及渗层抗高温氧化性研究

采用在20钢上复合电镀Ni-Y2O3层后再扩散渗铝的方法，得到了Y2O3改性的渗Al复合层，并对渗层氧化性能进行了试验研究。SEM及EDXA观察结果表明，经Y2O3改性的渗层，Y2O3颗粒均匀分布于渗层中，且表面铝含量达到30．65％。不连续氧化和循环氧化试验的结果表明，其抗高温氧化性能明显提高，分别为纯铝渗层的2．5倍和3倍。     

Research on testing method of resin sand high temperature compressive strength

High temperature compressive strength is one of the most important performances of resin sand; its value directly concerns the quality of castings. In order to seek the best testing method of resin sand high temperature compressive strength, a self-developed instrument was used to carry out experiments, and the sample shape and size were designed and studied. The results show that a hollow cylinder sample can reflect the strength difference of different resin sands better than a solid cylinder sample, and its data is stable. The experiments selected Φ20/5×30 mm as the size of the hollow cylinder samples. The high temperature compressive strengths of phenol-formaldehyde resin coated sand, furan resin self-setting sand, and TEA resin sand were each tested. For the resin sand used for cast steel and cast iron, 1,000 oC was selected as the test temperature; for the resin sand used for cast non-ferrous al oy, 800 oC was selected as the test temperature; and for all the resin sand samples, 1 min was selected as the holding time. This testing method can truthfully reflect the high temperature performance of three kinds of resin sand; it is reproducible, and the variation coefficients of test values are under 10%.     

Development of a new instrument for measurement of high temperature mechanical properties of resin-bonded sand

The mechanical properties of resin-bonded sand mixtures at high temperatures significantly affect the quality of casting. However, the existing instruments for high-temperature performances testing mainly focus on inorganic binder-bonded sands no matter the test items or the atmospheric protection, while the instrumentss specially designed for resin-bonded sand are not yet available. A new instrument for testing the hightemperature performance of resin sand was designed including the confirmation of the testing parameters, loading, measurement and control systems, and the design of the frame shape and heating furnace. This instrument can test the compressive strength, heat tolerance time and restraining load of phenol-formaldehyde resin coated sand, self-hardened furan resin sand, and trimethylamine(TEA)-based resin bonded sand at high temperatures. The developed instrument has a high accuracy offering smaller than 0.3% deviation at a full scale in the measurement of the high temperature compressive strength and the restraining load over the range of 0-6.8 MPa and 0-2,000 N, respectively. The high temperature heat tolerance time range is 0-300 s and its measurement accuracy is ±1 s.     

Application conditions for ester cured alkaline phenolic resin sand

Five organic esters with different curing speeds: propylene carbonate(i.e. high-speed ester A); 1, 4-butyrolactone; glycerol triacetate(i.e. medium-speed ester B); glycerol diacetate; dibasic ester(DBE)(i.e. lowspeed ester C), were chosen to react with alkaline phenolic resin to analyze the application conditions of ester cured alkaline phenolic resin. The relationships between the curing performances of the resin(including pH value, gel pH value, gel time of resin solution, heat release rate of the curing reaction and tensile strength of the resin sand) and the amount of added organic ester and curing temperature were investigated. The results indicated the following:(1) The optimal added amount of organic ester should be 25 wt.%-30 wt.% of alkaline phenolic resin and it must be above 20 wt.%-50 wt.% of the organic ester hydrolysis amount.(2) High-speed ester A(propylene carbonate) has a higher curing speed than 1, 4-butyrolactone, and they were both used as high-speed esters. Glycerol diacetate is not a high-speed ester in alkaline phenolic resin although it was used as a high-speed ester in ester cured sodium silicate sand; glycerol diacetate and glycerol triacetate can be used as medium-speed esters in alkaline phenolic resin.(3) High-speed ester A, medium-speed ester B(glycerol triacetate) and low-speed ester C(dibasic ester, i.e., DBE) should be used below 15 °C, 35 °C and 50 °C, respectively. High-speed ester A or lowspeed ester C should not be used alone but mixed with medium-speed ester B to improve the strength of the resin sand.(4) There should be a suitable solid content(generally 45 wt.%-65 wt.% of resin), alkali content(generally 10 wt.%-15 wt.% of resin) and viscosity of alkaline phenolic resin(generally 50-300 mPa·s) in the preparation of alkaline phenolic resin. Finally, the technique conditions of alkaline phenolic resin preparation and the application principles of organic ester were discussed.     

Curing mechanism of furan resin modified with different agents and their thermal strength

The curing mechanism of furfuryl alcohol and urea-formaldehyde furan resins was investigated using infrared spectroscopy (IR) technique. The curing productions of urea-formaldehyde furan resins modified with different agents (i.e. sorbitol, polyester poiyol, phenol and acetone) and the productions of incomplete curing were characterized by differential thermal analysis (DTA) and thermal gravity analysis (TG). The results indicate that except for polyester polyol, the other modifiers have little effect on the thermal strength of urea-formaldehyde furan resin. Furthermore, the thermal strength can be improved at a temperature of higher than 550℃.     

铸造用酚脲烷自硬树脂的高温力学性能研究

以酚脲烷树脂为主要研究对象,通过DMA检测不同温度下的酚脲烷树脂试样,绘制并分析了酚脲烷树脂0～400℃的DMA曲线,发现了酚脲烷树脂的玻璃态转变温度和良好阻尼性能的温度范围.通过对各温度点下数据的处理,分析了从室温至900℃树脂残留抗压强度的变化趋势及其变化原因.试验结果表明:酚脲烷树脂从300℃开始分解反应,导致强...     

用非晶钎料加中间层连接Si3N4陶瓷的试验

采用TiZrCuB非晶钎料并用Cu箔为中间层连接Si3N4陶瓷,研究了钎料成分、钎焊工艺和中间层厚度等对接头室温和高温强度的影响.结果表明:采用Ti40Zr25CuB0.2非晶钎料和70μm厚的Cu箔中间层,在1 323 K,30 min及0.027 MPa压力下钎焊连接Si3N4陶瓷,其接头在室温下的四点抗弯强度最高...