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p—Si上电沉积Ni—W—P薄膜的结构与热稳定性 总被引:3,自引:0,他引:3
研究了p-Si上恒电流沉积Ni-W-P合金薄膜组成与结构的关系,讨论了镀层的组成、结构随沉积时间的变化.测定了非晶合金的晶体结构随热处理温度的改变以及DTA曲线,结果表明,非晶Ni-W-P合金在晶化过程中形成两个纳米超微晶相,非晶Ni-W-P薄膜的热稳定性远高于通常使用的非晶Ni-P薄膜. 相似文献
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聚氨酯—聚丙烯酸树脂的合成及表征 总被引:4,自引:0,他引:4
讨论了在聚氨酯水分散体中进行丙烯酸酯共聚物乳液聚合的一些特征。研究表明,聚氨酯水分散体起着种子乳液的作用,发生了核-壳型事过程;复合乳液中聚氨酯链形成其壳,聚丙烯酸树脂分子链形成其核,二树脂的分子链相贯穿与缠结,形成了互穿网络结构。 相似文献
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聚(丙烯酰胺—丙烯酸)/聚(丙烯酰胺—二甲基二烯丙基氯化铵)聚电解质复… 总被引:7,自引:0,他引:7
通过动态光散射、粘度和透光率测定,研究了聚(丙烯酰胺-丙烯酸)[P(AM-AA)]/聚(丙烯酰胺-二甲基二烯丙基氯化铵)[P(AM-DMDAAC)]聚电解质复合溶液的结构和性能。结果表明,P(AM-AA)与P(AM-DMDAAC)复合比、溶液浓度和氯化钠用量影响溶液中复合物的构象和流体力学半径。P(AM-AA)与P(AM-DMDAAC)分子链间适度的库仑相互作用,可形成均相P(AM-AA)/P(A 相似文献
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多孔β—TCP生物降解陶瓷的红外光谱研究 总被引:5,自引:0,他引:5
本文报道了多孔β-TCP(β-Ca3(PO4)2)生物降解陶瓷的红外光谱,研究了实验条件对生物降解陶瓷结构与性能的影响,结果表明,生物降解陶瓷以βCa3*PO4)2米晶相,同时含有Ca2P2O7,Ca4P2O9晶相和其他非晶相,并呈现多孔的网络结构。 相似文献
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以具有良好柔性和生物相容性的聚四氢呋喃(PTHF)为疏水链段,具有pH敏感性的聚丙烯酸(PAA)为亲水链段,通过PTHF双端基大分子单体与丙烯酸自由基共聚,首次合成了聚丙烯酸-l-聚四氢呋喃(PAA-l-PTHF)两亲聚合物网络,并对网络的结构、组成以及交联点密度进行了表征。两亲聚合物网络溶胀行为研究表明,PAA-l-PTHF既能在水中溶胀又能在有机溶剂中溶胀,在水中的溶胀度随网络亲水链段PAA含 相似文献
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四元胶乳互穿聚合物网络的组成对其性能的影响 总被引:4,自引:0,他引:4
用分步乳液聚合法合成了具有核壳结构的胶乳互穿聚合物网络LIPN(PMMA-PS)/(Pn-BA-PAA);讨论了LIPN组成对乳液与膜性能的影响,提出了四元LIPN核壳结构的基本轮廓,探讨了软硬单体最佳配比及丙烯酸单体用量。 相似文献
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ZSM-5(核)/AlPO4-5(壳)双结构分子筛的合成与催化裂化性能 总被引:7,自引:0,他引:7
采用X射线衍射、扫描电镜、X射线能量散射谱、红外光谱和核磁共振等多种物化方法对合成的ZSM-5(核)/AlPO4-5(壳)双结构分子筛进行了表征,证明这种材料具有以ZSM-5为核层、以AlPO4-5为壳层的双结构特征.考察了合成条件对ZSM-5(核)/AlPO4-5(壳)分子筛形貌的影响,发现ZSM-5分子筛的加入方式对产物的形貌有较大影响.重油裂化反应结果表明,ZSM-5(核)/AlPO4-5(壳)双结构分子筛的催化性能比ZSM-5和ZSM-5/AlPO4-5机械混合分子筛样品好,表现为原油转化率和低碳烯烃、汽油及柴油收率提高. 相似文献
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β—环糊精交联聚合物树脂固定相分光光度法测定铜 总被引:6,自引:0,他引:6
利用β-环糊精交联合物(β-CDP)的选择性吸附性能和良好的透光性能,将其和为显色剂的载体用于分光光度法测定。首次提出了2-「5-溴-(2-吡啶偶氮)」-5-二乙基在苯酚(5-Br-PADAP)-环糊精交联树脂固定相分光光度法。方法用来自水及人发中微量铜的测定,简便快捷,准确可靠。 相似文献
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Anjie Dong Tong Wan Shiyou Feng Duoxian Sun 《Journal of Polymer Science.Polymer Physics》1999,37(18):2642-2650
The hydrogen bonds in films of the polyurethane and the core‐shell type polyacrylate‐polyurethane microemulsions have been studied by FTIR spectroscopy in the regions of NH absorption and CO absorption. The effects on hydrogen bonds of the composition, the core‐shell ratio were revealed. At the same time, the relationship between the hydrogen bonds and the crosslinked structures (Type A and Type B) was discovered. The shifts of the NH and CO stretching bands to higher frequencies and the shift of NH bending bands to lower frequencies, with the increase of acetone CO number in the core, mean that the hydrogen bonds between the soft and hard segments, and those in the short‐range order in the hard segment phase, are broken. The dipole/dipole interaction which is supposed to exist between the acetone CO groups in the core and the urethane CO in the shell can change the hydrogen bond distribution in the shell, and at the same time, lead to hydrogen bonds between acetone CO in the core and the urethane NH in the shell. Type A and B crosslinked structure between the core and the shell located at the interface of the core and the shell can confine the acetone CO within the crosslinking network, and Type B crosslinked structure also decreases the acetone CO numbers. These weaken the dipole/dipole interaction between the acetone CO and the urethane CO, and lead to the decrease of the effect of the acetone CO groups on the hydrogen bond distribution in the shell. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2642–2650, 1999 相似文献
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脂肪族水性聚氨酯的动态力学行为研究 总被引:4,自引:1,他引:4
合成了一系列脂肪族水性聚氨酯 .考察了软段的组成、软段分子量及DMPA用量对产物动态力学性能的影响作用 .实验结果表明 ,软段的化学结构对水性聚氨酯的相态结构影响很大 .聚醚型水性聚氨酯具有较低的软段玻璃化转变温度 (Tgs) .聚醚型产物的微相分离程度高于聚酯型产物 .当采用聚酯和聚醚二元醇为混合软段时 ,Tgs随软段中聚醚含量的提高而逐渐降低 .提高DMPA用量 ,软段玻璃化转变温度Tgs移向低温区 ,硬段玻璃化转变温度Tgh移向高温区 ,说明体系的微相分离程度加大 .当软段分子量较低时 ,产物为半相容结构 ,只有一个主转变峰 ,软段的玻璃化转变以肩峰的形式出现 ;当软段分子量较高时 ,产物的微相分离程度较高 ,可以分别观察到软段及硬段的玻璃化转变 .总之 ,通过改变软段的种类、组成和分子量以及DMPA用量 ,可以大幅度地改变水性聚氨酯的形态结构 . 相似文献
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聚乙二醇型聚氨酯软硬段对其相变储热性能的影响 总被引:2,自引:0,他引:2
以不同分子量的聚乙二醇(PEG)为软段,MDI-BDO为硬段,采用两步法溶液聚合合成一种具有固-固相变储热性能的聚氨酯材料.通过DSC,WAXD等测试手段对体系的软硬段结晶性,微相分离,相变可逆性及循环热稳定性进行研究,结果表明,聚氨酯中硬段的存在对软段结晶有着很大的影响,当软段分子量达到2000或以上时,软段才具有较大的结晶度和熔融相变焓,且硬段含量必须高于一定值才能形成较为完善的物理交联网络以保证材料在发生相变时维持固体状态.同时符合这两个条件的试样能具有较好的固-固相变储热性能.就软段PEG含量及分子量对材料储热性能的影响进行了研究,通过调节软段含量与分子量得到一系列具有不同相变焓和相变温度的聚氨酯固-固相变储热材料.经测试还发现,该材料具备很好的相变可逆性和循环热稳定性,是一类很有开发前景的相变储热材料. 相似文献
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X. Yu M. R. Nagarajan C. Li P. E. Gibson S. L. Cooper 《Journal of Polymer Science.Polymer Physics》1986,24(12):2681-2702
A series of polyurethane block copolymers based on hydroxybutyl terminated poly(chloropropylmethyl-dimethylsiloxane) and poly(tetramethylene oxide) soft segments of molecular weights 2100 and 2000, respectively, were synthesized. The hard segments consisted of 4,4′-methylenediphenylene diisocyanate (MDI) that was chain extended with either 1,4-butanediol (BD) or N-methyldiethanolamine (MDEA). The materials chain extended with MDEA were ionized using 1,3-propane sultone. The weight fraction of the hard segments was in the range 0.30–0.45. The effect of mixed soft segments, chain extenders, and zwitterionization on the extent of phase separation and physical properties was studied by utilizing differential scanning calorimetry and dynamic mechanical, stress-strain, and Fourier Transform Infrared spectroscopy experiments. All of these short segment block copolymers showed nearly complete phase separation. The zwitterionomer materials exhibited ionic aggregation within the hard domains. Although hard segment crystallinity or ionic aggregation did not affect the morphology, hard domain cohesion was important in determining the tensile and viscoelastic properties of these elastomers. 相似文献
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Multiblock poly(ester-block-amide)s (PEA) elastomers comprising hard blocks of oligoamide and oligoester soft segments were prepared and their structure-property relations were analysed. The polycondensation reaction of oligoesters (prepared from 1,4-butanediol and dimerized fatty acid) with oligolaurolactam (PA12) gave copolymer series with variable blocks content (the soft segments content was varied from 24 to 60 wt.%). PEAs are the phase system composed of crystallised sequences of oligoamide (hard segment phase) as well as oligoesters (soft segment phase). Mixing between the hard and soft phases was studied by thermal and mechanical measurements (DSC, DMTA). These results have indicated on a multiphase structure of investigated materials. The relationship between the observed thermal and tensile properties and the soft/hard segments content indicated on an increase of the phase separation with soft segments content. 相似文献
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Versatile Preparation of Nonspherical Multiple Hydrogel Core PAM/PEG Emulsions and Hierarchical Hydrogel Microarchitectures 下载免费PDF全文
Song Guo Tong Yao Xiaobo Ji Prof. Changfeng Zeng Prof. Chongqing Wang Prof. Lixiong Zhang 《Angewandte Chemie (International ed. in English)》2014,53(29):7504-7509
The preparation of nonspherical materials composed of separated multicomponents by droplet‐based microfluidics remains a challenge. Based on polymerization‐induced phase separation and droplet coalescence in microfluidics, we prepared emulsions of variously shaped PAM/PEG core/shell droplets and hydrogels composed of two separated components, which show flexible and transformable hierarchical structures and microarchitectures. We find that AM/PEG aqueous droplets form a core/shell structure after polymerization resulting from phase separation. Thus multicore/shell droplets are easily produced by coalescence of core/shell structures. By changing the polymerization temperature and the flow rate, the morphology of the multicore droplets and the hydrogel can be easily adjusted. The hydrogels exhibit apparent anisotropy and different protein release rates depending on their structures. The preparation technique is simple and versatile and the resulting hydrogels have potential applications in many fields. 相似文献
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Fabrice Domingues Dos Santos Pascale Fabre Xavier Drujon Gilles Meunier Ludwik Leibler 《Journal of Polymer Science.Polymer Physics》2000,38(23):2989-3000
Structured latexes provide a promising route to hard coatings without the use of coalescing aids. We studied the thermomechanical properties of films from structured soft‐core/hard‐shell hydrophobic latexes. We found that the mechanical properties of these films were closely related to their very particular organization. When the rigid phase was continuous, whatever its volume fraction, the films exhibited a high elastic modulus. An analysis of the viscoelastic properties of the films provided a good method for obtaining information about the interphase between the hard shell and soft core of the latex particles. By varying the film structure through annealing or the particle composition (core/shell ratio, core crosslinking, etc.), we were able to tune the mechanical properties of the films. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2989–3000, 2000 相似文献