共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
球形ADN的吸湿机理 总被引:1,自引:0,他引:1
用动态吸湿性分析法和扫描电镜研究了球形二硝酰胺铵(ADN)的吸湿过程和吸湿过程中ADN形貌的变化,探讨了ADN的吸湿机理。结果表明,ADN吸湿过程可分为平缓吸湿(Ⅰ),急剧增强吸湿(Ⅱ)和潮解(Ⅲ)三个阶段,Ⅰ、Ⅱ阶段是水蒸汽与ADN固体表面的作用,Ⅲ阶段是水蒸汽与ADN液化膜表面的作用。Ⅰ阶段吸湿过程为多分子层吸附,符合BET理论模型;该阶段水与ADN之间的作用力对ADN吸湿性能起主导作用;Ⅱ阶段吸湿机理可用毛细孔凝聚理论解释,影响该阶段ADN吸湿性能的主要因素是ADN表面的光滑程度。 相似文献
3.
以正硅酸乙酯、无水乙醇、去离子水为原料制备胶液后,真空浸渍石英纤维复合材料,经固化、超临界干燥成型、表面改性等工艺使其内部填充纳米级的SiO2.利用阿基米德法测试了材料的吸水率和显气孔率,利用BET法和短路波导法对气凝胶的比表面积和孔径以及材料的介电性能进行了表征,并分析了憎水机理.结果表明,填充前后复合材料的吸湿率由最初的17.36%降至1.21%,降幅高达93%,辅以防潮涂层后吸湿率更可低至为0.052%;介电常数基本没有变化,损耗角正切有所降低,降幅最高达51.2%. 相似文献
4.
5.
第三十讲聚氨酯塑胶跑道研究及应用进展 总被引:2,自引:0,他引:2
介绍了国内MDI型聚氨酯塑胶跑道树脂技术研究进展,介绍了表面无颗粒跑道、纳米塑胶跑道技术、无防滑颗粒塑胶跑道技术、低成本塑胶跑道技术等技术进展,同时介绍了聚氨酯塑胶跑道的应用意义、机理和最新应用进展,分析了MDI型聚氨酯塑胶跑道代替TDI型塑胶跑道的优势。 相似文献
6.
7.
综述了空气取水的基本研究现状,对可用于空气取水的固体吸附剂、液体吸收剂、复合吸湿材料以及新型吸湿技术等各类吸湿材料的研究现状和发展趋势进行了详细的讨论,并对冷却结露式取水方法与吸湿/解吸式取水方法的能源利用方式进行了讨论和比较。在此基础上,对采用吸湿/解吸方法同时合理利用太阳能和余热来取水的研究前景进行了展望。 相似文献
8.
二硝酰胺铵防吸湿技术研究进展 总被引:1,自引:0,他引:1
二硝酰胺铵(ADN)的吸湿性是影响其广泛应用的一个主要原因.从ADN的吸湿原因、吸湿机理、防止吸湿方法几方面介绍了ADN防吸湿技术的研究进展,并指出了我国今后ADN防吸湿技术的发展方向. 相似文献
9.
10.
11.
聚氨酯防水透湿涂层剂的合成 总被引:2,自引:0,他引:2
以聚丙二醇(PPG)/聚乙二醇(PEG)混合多元醇作为聚醚二醇组分,与二苯基甲烷二异氰酸酯(MDI)进行预聚,然后用1,4-丁二醇扩链合成有防水透湿性的聚氨酯涂层剂,经红外光谱分析确定为目标产物。研究了不同的工艺条件对涂层剂合成的影响,讨论了R值〔n(—NCO)/n(—OH)〕对涂层剂黏度的影响。结果表明,n(MDI)∶n(聚醚二醇)=1.42∶1,反应温度82℃,预聚反应时间1h,扩链反应时间2h,R值为1.02~1.07时,制得的涂层剂耐静水压值达到20.4kPa,透湿量达到4533g/(m2·d)。经与比利时UCB公司的产品UCcoat2000和日本Toray公司的产品EntrantGⅡTX进行比较,本涂层剂耐静水压和透湿量指标更优越。 相似文献
12.
从聚合、纺丝以及假捻变形工艺等方面对共聚型抗紫外吸湿排汗细旦异形涤纶长丝的生产进行了探讨。试验证明:采用聚合法制得抗紫外PET切片,然后采用细旦异形纺丝工艺,制得抗紫外POY,再在假捻变形机上进行后加工。采用整理型吸湿排汗油剂,提高产品吸湿排汗性能,可以制得染色及上述性能好的涤纶长丝DTY。 相似文献
13.
14.
The influence of moisture absorption on the extent of the boundary interphase in particulate composites is thoroughly studied. It was found that, during the process of moisture absorption there is a variation of the extent of the boundary interphase, closely related to the degradation of the mechanical behavior of the composite, as well as to the percentage amount of moisture absorbed. An explanation of the observed relationship was advanced, based on a theoretical mechanism of absorption. This study complements a previous one, where the observed degradation of the thermomechanical properties of particulate composites due to moisture absorption was shown to be intimately interrelated with the state and extent of the interphase between fillers and matrix. 相似文献
15.
16.
17.
An investigation of the effect of modifying the network structure on moisture absorption of epoxies was performed. The network was modified by crosslinking the epoxides with various mono/diamine proportions, resulting in decreasing density and increasing free volume. It was discovered, however, that concomitant effects, i.e., the formation of a two-phase structure, and changes in resin polarity and in resin–water affinity predominated. Thus, compositions with higher chain molecular weights between crosslink points yet exhibited lower diffusion coefficients. Also, when drastic swelling conditions (such as a water-boil treatment) were employed, moisture absorption was facilitated by penetration via newly formed microcracks. 相似文献
18.
This paper presents a methodology for predicting moisture concentration in an epoxy adhesive under cyclic moisture absorption-desorption conditions. The diffusion characteristics of the adhesive were determined by gravimetric experiments under cyclic moisture conditions and the dependence of diffusion coefficient and saturated mass uptake on moisture history was determined. Non-Fickian moisture absorption was observed during absorption cycles while moisture desorption remained Fickian. The diffusion coefficient and saturated moisture content showed variation with absorption-desorption cycling. A finite element-based methodology incorporating moisture history was developed to predict the cyclic moisture concentration. A comparison is made between the new modelling methodology and a similar method that neglects the moisture history dependence. It was seen that the concentration predictions based on non-history dependent diffusion characteristics resulted in over-prediction of the moisture concentration in cyclic conditioning of adhesive joints. The proposed method serves as the first step in the formulation of a general methodology to predict the moisture dependent degradation and failure in adhesives. 相似文献
19.
聚氨酯/丁腈橡胶互穿网络型吸水膨胀橡胶的性能研究 总被引:2,自引:0,他引:2
将丁腈橡胶与高吸水树脂(SAP)、增强剂、聚乙二醇(PEG)和二苯基甲烷二异氰酸酯(MDI)等在开炼机上充分混合,在高温下PEG和MDI发生逐步聚合反应,与丁腈橡胶原位互穿,得到互穿网络型吸水膨胀橡胶(IPN-SWR)。研究了聚氨酯(PU)用量对互穿网络型吸水膨胀橡胶的机械性能和吸水膨胀性能的影响。结果表明,随着PU含量升高,橡胶的机械性能下降,吸水速率加快,最大质量膨胀倍率(ΔWe)先升高后降低,质量损失率降低,循环测试次数越高,膨胀性能下降,质量损失率变小。同种材料的胶筒制品的膨胀速率远远小于试片的膨胀速率。 相似文献