聚硅氧烷嵌段/接枝改性聚氨酯的表面性能

以不同结构的端羟基聚硅氧烷（PDMS）为软段,聚己内酯（PCL）为混合软段,通过与异佛尔酮二异氰酸酯（IPDI）加聚合成了一系列嵌段/接枝型硅氧烷改性聚氨酯（PDMS-PU）,并采用静态接触角、接触角滞后以及XPS等表征手段分析了硅氧烷链段在聚氨酯主链中的链接方式对其表面性能的影响.结果表明：2种链接方式的硅氧烷均能有效的降低聚氨酯的表面能,引入质量分数为15% 的硅氧烷,便可使得其水接触角达到110°,侧链接枝型由于硅氧烷位于侧链,自由度高,链段运动能力较强,易于形成表面富集.主链嵌段型由于硅氧烷链段两端均固定在主链上,难以发生表面重构,接触角滞后不明显,而侧链接枝型硅氧烷链段位于侧链,容易发生表面重构,使得部分极性亲水的聚氨酯硬段暴露在表面,其接触角滞后较为严重.     

侧链含PDMS的改性PUA复合乳液的制备与性能

采用阴离子自乳化法合成了聚氨酯分子侧链上含聚二甲基硅氧烷（PDMS）的改性水性聚氨酯-丙烯酸酯系列复合乳液（SiPUA）,主要探讨了氨乙基氨丙基聚二甲基硅氧烷（AEAPS）含量对SiPUA乳液及其涂膜性能的影响．结果表明,AEAPS在SiPUA中质量分数为6％时,乳液稳定性良好;涂膜的吸水率明显降低,断裂伸长率增加,但拉伸强度有所减小．     

高阻尼性能聚氨酯的结构设计与研究

根据基团贡献分析法和聚合物阻尼性能定量化理论，设计合成了主链和接枝链均为甲苯环二异氰酸酯与聚氧化丙烯醚的反应产物的聚氨酯弹性体。动态力学性能测试表明：该弹性体的相间相容性好，阻尼性能优异。主链软段的分子量和接枝链上软段的含量对聚氨酯的阻尼性能有较大的影响，主链上软段的平均分子量大，接枝链上软段的含量小，材料的阻尼性能好。原子力显微镜(AFM)分析结果表明：含接枝链的试样，硬段与软段界面模糊，相畴小，两相的相容性好，表明接枝链引入，增强了软段和硬段之间的相互作用，使硬段与软段的相容性增加。     

软段对微孔聚氨酯弹性体性能的影响

选用不同种类二元醇和二苯基甲烷二异氰酸酯、1,5-萘二异氰酸酯等为原料,采用半预聚法制备微孔聚氨酯弹性体,研究了软段对微孔聚氨酯弹性体力学性能、动态性能及老化性能的影响。结果表明,软段为CP10时,材料的强度最高,弹性较差。软段为聚己内酯醇时,材料的玻璃化转变温度较高,损耗峰也较高。经热水老化后,材料的强度下降,拉断伸长率增加,软段为聚己内酯醇时,材料强度下降较大。     

硬段侧链含有双季铵盐的聚氨酯的合成及表征

为了解决单铵盐抗菌聚氨酯存在的对革兰氏阴性细菌抗菌性能差、扩链剂用量大的问题,合成了硬段侧链含有双季铵盐的系列聚氨酯。用GPC和核磁共振研究了材料的分子量和结构,表明双季铵盐扩链剂成功引入了聚氨酯主链。通过傅立叶变换红外光谱(FTIR)和差热分析(DSC)研究了材料的本体微相分离结构。发现,随着双季铵盐含量的增大,材料的软段和硬段之间的氢键结合增加,微相分离程度降低。     

软段种类对聚氨酯弹性体性能的影响

采用预聚体法,以二甲硫基二氨基甲苯(DMTDA)为扩链剂合成TDI体系的浇注型聚氨酯弹性体(PUE),研究了软段多元醇种类对聚氨酯弹性体分子结构、力学性能、耐热空气老化、耐水解和动态性能的影响。实验发现:聚酯型PUE的拉伸强度、撕裂强度、硬度等力学性能和耐热空气老化性能优于聚醚型,尤以聚己内酯型(PCL)为优;聚醚型的弹性、耐高温水解性、低温性能和动态性能则明显优于聚酯型,尤以PTMG为优。     

环氧树脂改性聚氨酯弹性体

利用环氧树脂(E-51)与聚氨酯预聚体NCO的反应,得到改性聚氨酯弹性体(PUE),并考察了PUE的物理性能。实验结果表明:E-51质量分数为5%时,PUE的邵尔A型硬度、拉伸强度、100%定伸应力和撕裂强度达到最小值,分别为86、15.9 MPa、2.5 MPa和32.1 N.mm-1,而扯断伸长率为457%;E-51提高了PUE的耐热性;E-51质量分数为5%时,PUE的耐溶剂性差,耐四氢呋喃最差,环己酮次之,乙酸乙酯最好。     

聚天冬氨酸酯聚脲的动态力学行为研究

通过聚天冬氨酸酯（PAE）与脂肪族异氰酸酯六亚甲基二异氰酸酯（HDI）三聚体／聚四亚甲基二醇（PTMG）预聚物反应，合成了一系列PAE聚脲，考察了PAE种类、软段分子量及成型温度对聚脲动态力学性质的影响。实验结果表明，三官能度PAE-F扩链的聚脲具有较高的低温和高温储能模量（E’）及硬段玻璃化转变温度（Tgh），其微相分离程度也高于二官能度PAE—α扩链的聚脲。软段分子量较高的聚脲向于微相分离。室温成型的聚脲为半相容结构，成型温度提高至60℃时，呈现微相分离结构。     

聚偏氟乙烯含量对共混微孔膜结构与性能的影响

为了探究固含量对共混微孔膜的结构与性能的影响,以液体石蜡和邻苯二甲酸二丁酯为复合稀释剂,通过热致相分离法制备了聚偏氟乙烯(PVDF)/超高分子质量聚乙烯(UHMWPE)共混平板微孔膜;利用差示扫描量热仪测试铸膜液的结晶性能,采用场发射电子显微镜观察膜表面形貌,并通过孔隙率、接触角和拉伸强度表征微孔膜的性能。结果表明:UHMWPE以原纤网络结构连接PVDF球晶;随着PVDF含量的增加,共混膜的结晶度由3.2%增加到8.0%,接触角由85°增加到107°,孔隙率由27%降低到21%,拉伸强度提高了近59%。     

脲基的引入对聚氨酯弹性体性能的影响

使用单乙醇胺作为部分扩链剂将脲基引入到聚氨酯分子链中,利用IR、DSC、电子拉伸机等研究了脲基的引入对聚氨酯弹性体的影响。研究结果表明:使用单乙醇胺作为部分扩链剂能够促进聚氨酯弹性体硬段部分的聚集,从而提高其力学性能。     

乙二醇和不同相对分子质量聚乙二醇对聚氨酯多孔膜性能的影响

采用乙二醇和不同相对分子质量的聚乙二醇作为聚氨酯多孔膜的致孔剂,通过对聚氨酯多孔膜的电镜图、透湿性、接触角以及拉伸性能的表征与分析,探究乙二醇和不同分子量聚乙二醇的用量对聚氨酯微孔膜结构和性能的影响。结果表明：采用乙二醇,添加量在50％时,透湿量达到2929 g/（m2· d ）;断裂强力与断裂伸长率分别在5．77 M Pa ,451．3％,说明得到的聚氨酯多孔膜具有较高的透湿量、孔隙率以及较强的拉伸性。     

葡萄糖改性水性聚氨酯的制备及性能研究

以二羟甲基丙酸(DMPA)、葡萄糖(PG)为亲水扩连剂和交联剂制备一系列改性阴离子水性聚氨酯自乳化乳液,并制备了改性聚氨酯的固化膜.通过FT-IR对聚合物结构及其膜性能进行了表征,通过动态激光光散射法(DLLS)测定了乳液粒径,并分析了乳液的稳定性、流变性能及固化膜的耐水性、力学性能.FT-IR分析表明葡萄糖已引入聚氨酯主链.随着PG用量的增加,乳液稳定性略有下降.乳液体系的弹性模量G′,损耗模量G″均随着振荡频率的增加而增大.聚氨酯胶膜的耐介质性、力学强度均得到改善.当PG的用量由0%增加至4.68%时,膜的吸水率和吸溶剂率下降,拉伸强度从10.9MPa增加至24.2MPa.     

Effect of carbon fibre on properties of TiB2/C composite cathode coating for aluminum electrolysis

The tensile strength, compressive strength and electrical resistivity of TiB₂/C composite cathode coating were measured with a hydraulic pressure universal test machine and an electrical resistivity test device, and the effects of carbon fibre content and carbon fibre length on tensile strength, compressive strength and electrical resistivity were investigated. The results show that the tensile strength of coating increases at the beginning and then reduces with the increase of carbon fibre content when the carbon fibre (length of 3 mm) content ranges from 0 to 4.0%; at the carbon fibre content of 1.5%, the tensile strength of coating reaches the maximum, 25.6 MPa. For the coating with carbon fibre content of 1.5%, the carbon fibre length has a great influence on tensile strength and compressive strength of coating; when the carbon fibre length is 6 mm, the tensile strength and compressive strength of coating reach the maximum, 27.6 MPa and 39.2 MPa, respectively. The electrical resistivity of coating reduces with the rise of temperature and the length of carbon fibre, and the influence of carbon fibre length on electrical resistivity of coating at low temperature (30–200 °C) is more obvious than that at high temperature (960 °C). Foundation item: Project(2005CB623703) supported by the Major State Basic Research Development Program of China     

PTFE膜材料的偏轴拉伸性能及破坏机理

为深入把握PTFE膜材料的率相关力学性能及破坏机理,对3种常见的PTFE膜材料进行了偏轴拉伸试验,主要考虑了0°、5°、15°、25°、35°、45°、55°、65°、75°、85°、90°等11个偏轴角度和10、25、50、100、200、500 mm/min等6种拉伸速率,分析了主要力学参数的变化规律,研究了不同拉伸速率下的膜材破坏模式及破坏机理.结果表明:不同拉伸速率下膜材主要力学参数的变化规律比较一致,表现出明显的各向异性;材料的抗拉强度与破坏模式密切相关,随着拉伸速率的增加,抗拉强度逐渐升高,且与拉伸速率的对数呈近似线性关系,这主要与材料应变能及编织结构有关;材料的破坏模式和断裂延伸率受拉伸速率的变化影响不明显.     

Effects of Ag on microstructure and mechanical properties of 2519 aluminum alloy

The effects of Ag on the microstructure and mechanical properties of 2519 aluminum alloy were investigated by means of tensile test, micro-hardness test, transmission electron microscope and scanning electron microscope. The results show that the addition of 0.3 % （mass fraction） Ag accelerates 2519 aluminum alloy＇s age-hardening, increases its peak hardness and reduces 4 h of peak aged time at 180 ℃. The addition of 0. 3% （mass fraction） Ag increses the tensile strength at room temperature and elevated temperature. This increment at room temperature and 200 ℃ is 24 MPa and 78 MPa, respectively. In contrast, the elongation of 2519 aluminum alloy is decreased with Ag addition. The increase of tensile strength of 2519 aluminum alloy with Ag addition is attributed to the high volume fraction of Ω phase.     

Effect of roughness on wettability and floatability: Based on wetting film drainage between bubbles and solid surfaces

Wetting film thinning measurement was introduced to clarify the wettability and floatability of solid surfaces with varying roughness. The wettability was quantified using the contact angle measurement combined with the dynamic force microbalance test between solid surfaces and water droplets, while the floatability was investigated by the bubble-solid surface dynamic attachment observation and the induction time measurement. The results show that the water contact angles reduce (14.53°, 12.74°, and 6.71°) with the increase of glass surface roughness, while the water droplet-glass adhesion forces intensify (11.1, 19.1 and 19.2 μN) owing to the stable wetting film. The distortion of the contact surface and the Wenzel state are the causes. In contrast, the hydrophobized surfaces have the growing apparent contact angles (38.08°, 69.81°, and 81.01°), declining adhesion strength and shortening induction time (863, 352 and 12 ms) along with the increasing surface roughness. The weak wettability and fine floatability on the rough hydrophobized surface is reflected in the fast wetting film drainage dynamics and three-phase contact formation, which may be attributed to the wetting film with short diameter on tiny rough nubs and the entrapped air in the grooves as a bridge between the bulk bubble and the solid surface.     

聚乙二醇基形状记忆水性聚氨酯的合成与性能研究

用不同相对分子质量的聚乙二醇(PEG)为软段,以IPDI-BDO-DMPA为硬段,合成出一系列含有可结晶软段的水性聚氨酯材料,并通过红外、DSC以及形状记忆性能测试等手段对样品的软段结晶性和形状记忆功能进行表征.结果表明:软段相对分子质量、硬段含量都对软段的结晶性有很大的影响;只有PEG相对分子质量大于2 000时合成的聚氨酯的软段才具有结晶性,并且软段的熔融温度和熔融焓会随着PEG相对分子质量的增大而增大;若软段的相对分子质量一定,则样品的熔融温度和熔融焓会随着硬段含量的增加而呈现减小的趋势;当软段为PEG 4 000、硬段质量分数为30%时,该材料表现出良好的形状记忆性能.     

Effects of quenching process on mechanical properties and microstructure of high strength steel

The effects of direct quenching and tempering (DQ-T) process and conventional reheat quenching and tempering (RQ-T) processes on mechanical properties and microstructure of high strength steel were investigated. The DQ process was found to enhance the hardenability of steel effectively. The tensile strength and yield strength of DQ specimen was 975 MPa and 925 MPa respectively, which were higher than those of RQ specimen??s of 920 MPa and 871 MPa. In contrast, low temperature toughness (?40 °C, AKV) of DQ-T specimen (124 J) was generally inferior to that of RQ-T specimen (156 J). The direct quenching temperature was one of the potential process parameters to determine strength/toughness balance of steel manufactured by DQ process. The experimental results showed that excellent strength/toughness balance was obtained when the specimens was quenched at temperature in the range of 850?C910 °C. The yield strength and impact energy (?40 °C) of DQ steel decreased significantly with increasing of quenching temperature, although the tensile strength was nearly stable.     

微晶高岭石/环氧树脂复合改性水性聚氨酯的研究

用十六烷基三甲基溴化铵,十二烷基三甲基溴化铵,对微晶高岭石进行有机化处理,得到有机微晶高岭石;以有机微晶高岭石、环氧E-51复合改性,制备了有机微晶高岭石/环氧树脂复合改性的水性聚氨酯（OMMT/E-51WPU）。研究了有机微晶高岭石、2,2-二羟甲基丙酸和环氧E-51的质量分数对乳液及涂膜物化性能的影响。结果表明：当w（OMMT）=1.5%,w（DMPA）=4.0%,w（E-51）=4.0%,乳液及膜的物化性能较好,乳液呈透明蓝光,吸水率为5.9%,接触角98°,拉伸强度32MPa,断裂伸长率571%。