软段结构对脂肪族聚氨酯弹性体的结构与性能影响

分别采用聚丙二醇(PPG)、聚四氢呋喃二元醇(PTMG)、聚己二酸一缩二乙二醇三羟甲基丙烷酯多元醇(726)和聚己二酸新戊二醇酯二元醇(756)4种不同软段制备了基于异佛二酮二异氰酸酯(IPDI)的脂肪族聚氨酯弹性体(PUE),并通过FT-IR、DSC和TGA等表征了软段结构对PUE结构与性能的影响。结果表明,在相同硬段含量的条件下,PTMG制备的PUE具有最高的交联密度和最低的氨酯羰基氢键化程度。聚酯型PUE的耐热性和热氧老化性能均优于聚醚型PUE,由756合成的PUE具有最好的老化性能和热稳定性。     

聚醚型与聚酯型聚氨酯弹性体的性能研究

使用聚乙二醇(PEG)、聚四亚甲基醚二醇(PTMG)、聚己内酯(PCL)和4,4’-二苯基甲烷二异氰酸酯(MDI)合成了聚醚多元醇型和聚酯多元醇型热塑性聚氨酯弹性体(TPU)。研究了各种TPU中异氰酸酯指数(R0)、硬段浓度(Ch)、聚醚和聚酯的种类、摩尔质量及原料用量等对弹性体力学性能的影响;并且使用双酚A型环氧树脂NPEL-127改性了弹性体的耐热性。研究结果表明:TPU的硬度随着R0和Ch的增加而增加;聚醚型TPU中,随着软段中柔性链的增加,TPU的硬度下降而力学性能提高;聚酯型TPU中,随着聚酯和聚酯二元醇摩尔质量的提高,TPU的硬度和力学性能均有提高;聚酯型TPU的力学性能优于聚醚型TPU;环氧树脂改性使得聚醚型TPU耐热性提高。     

聚酯聚醚混合型水性聚氨酯木器漆的合成及性能

以甲苯二异氰酸酯(TDI)为硬段,聚醚二元醇(N210),磺酸聚酯二元醇(BY3301),聚己二酸丁二醇酯二醇(PBA)为软段合成了一系列水性聚氨酯(WPU),通过调节大分子多元醇的比例,探讨WPU性能的变化。红外测试表征了水性聚氨酯的结构;吸水率、硬度、拉伸强度及热性能测试表明,随着N210含量的增加,聚氨酯胶膜硬度增加、吸水率降低,拉伸强度先增加后降低,最大可达41.61 MPa;随着BY3301含量的增加,胶膜的硬度、吸水率、以及拉伸强度均有增加。     

聚醚-聚酯型水性聚氨酯胶粘剂的合成

文章以聚醚二元醇、聚酯二元醇为软段,以甲苯二异氰酸酯、1,4-丁二醇等为硬段,采用两步法合成水性聚氨酯胶粘剂。研究了亲水基团的含量、异氰酸酯基(-NCO)与羟基(-OH)的摩尔比、聚醚/聚酯二元醇复配比例等对水性聚氨酯胶粘剂性能的影响。结果表明:亲水性基团含量1.5%～1.7%,异氰酸酯基与羟基的摩尔比为1.13～1.27,聚醚/聚酯复配比例为25/75～35/65时所合成的胶粘剂对BOPP/PET软包装复合材料有较佳的粘结性能。     

水性聚氨酯结构与性能关系研究

以聚酯二元醇（PHA）、聚醚二元醇（N-210、N-220）、蓖麻油（C．O．）、甲苯二异氰酸酯（TDI）、二羟甲基丙酸（DMPA）为主要原料合成了系列水性聚氨酯（WPU），并对聚醚N-220型WPU分别使用有机硅、有机氟、端羟基聚丁二烯（HTPB）橡胶改性。通过红外、吸水率测试、电子拉力试验机、接触角测试研究了软段类型（N-210，N-220，PHA）、交联、改性对WPU耐水性、力学性能、涂膜手感的影响。研究发现，由PHA制备的聚氨酯耐水性、拉伸强度优于聚醚（N-210、N-220）制备的聚氨酯，适度交联可提高胶膜拉伸强度及耐水性。有机硅、有机氟改性可改进WPU的耐水性及表而性能，HTPB橡胶改性可提高胶膜的柔顺性及力学性能。     

聚氨酯弹性体的动态力学性能的影响因素

综述了聚氨酯弹性体动态力学性能的多种影响因素,讨论了软段类型(聚酯和聚醚)、软段相对分子质量、硬段类型(二异氰酸酯和扩链剂)、硬软段质量分数对PU弹性体动态力学性能的影响。在PU弹性体中,聚酯软段比聚醚软段的Tg高,弹性模量依PPG、PEG、PTMG软段顺序增加。     

HTPS改性聚氨酯乳液的表征及表面性能探讨

以烷羟基聚二甲基硅氧烷（HTPS）、聚醚和聚酯二醇作为复合软段,制备了系列有机硅改性的聚醚．聚酯型聚氨酯乳液。通过衰减全反射红外光谱及表面光电子能谱研究证实,有机硅链段已键入聚氨酯分子链中,且硅氧烷链段有表面富集的倾向。表面水接触角测试结果则表明,胶膜的水接触角随着有机硅含量的增加而增大,随着成膜温度的提高,先增大后降低。     

聚醚-酯嵌段共聚物改性微孔聚氨酯弹性体性能的研究

采用双金属氰化物络合催化剂（DMC），以脂肪族己二酸系聚酯多元醇为起始剂，与环氧丙烷（PO）、环氧乙烷（EO）进行烷氧基化反应，制得聚醚酯多元醇用于微孔聚氨酯弹性体（MPUE）的合成，可得到综合性能优良的MPUE材料。在相同硬段含量下，聚醚酯型MPUE的力学性能接近聚酯型MPUE，优于聚醚型MPUE，并且其耐水解性能得到较大的提高，接近聚醚型MPUE。     

PBT—PTMG嵌段共聚酯的研究

对以对苯二甲酸二甲酯、1,4-丁二醇和四氢呋喃聚醚二元醇为原料,钛酸四丁酯为催化剂制备PBT—PTMG嵌段共聚酯的工艺方法进行了研究。制备了软硬段比不同的PBT—PTMG嵌段共聚酯切片,并对其性能进行了表征。其结果显示,PBT—PTMG嵌段共聚酯的密度和硬度都随PBT含量的增大而增大,吸水率随聚醚含量增大而增大;调节PBT-PTMG嵌段共聚酯的组成可以得到具有不同力学性能的产物,且具有良好韧性。     

聚酯／聚醚混合型聚氨酯的形态结构及性能

本文首次以六次甲基二异氰酸酯,环氧乙烷封端聚环氧丙烷二醇,聚己二酸丁二醇酯二醇和1,2—丙二醇为原料,制备了一系列不同聚酯、聚醚含量的聚酯/聚醚混合型聚氨酯,并借助WAXD,FTIR及电子拉伸实验机等,对材料的结晶性,微观相分离及力学性能进行了研究。结果表明,聚醣聚醚混合作为软段,对聚氨酯的力学性能有良好的协同效应。聚酯/聚醚配比为35/65时,样品的结晶性及微相分离程度最大,力学性能最佳。     

Mechanical,thermal, and electric properties of polyurethaneimide elastomers

Linear polyurethaneimide elastomers (PUI) were obtained from polyether- or polyester-diols, diphenylmethane diisocyanate or bitolylene diisocyanate and pyromellitic acid dianhydride. It was found that these polymers have considerably better mechanical properties than typical linear polyurethanes (PU). The elastic modulus and stress at break increase with contents of the hard polyimide segments. The softening temperatures and thermal stability of the PUI at 500°C were higher than the ones of PU with similar hard segment contents. Electric properties of PUI were close to the ones of conventional PU. It was shown that cellular PUI had considerably lower dielectric constant. T_g's of the soft segments PUI were less than T_g's corresponding to PU. It is connected with greater phase separation of the hard imide segments from the soft polyether– or polyester–urethane matrix.     

嵌段聚醚酯弹性纤维的老化及热分解

通过测定以PBT为硬段 ,聚乙二醇 (PEG)和聚丁二醇 (PTMG)为软段的嵌段聚醚酯弹性纤维在老化前后的特性粘数、断裂强度、断裂伸长率和弹性回复率的变化 ,发现添加抗氧剂能明显改善该弹性纤维的抗老化性能并提高纤维的力学性能和回弹性能 ;采用热失重测定了PBT -PTMG2嵌段聚醚酯弹性纤维的热分解性能 ,热分解动力学计算表明其热分解活化能较低 ,为 69.6kJ ,容易热分解 ,热分解为 1级反应     

Water vapor permeability and mechanical properties of fabrics coated with shape‐memory polyurethane

Water vapor permeable fabrics were prepared by coating shape‐memory polyurethane (PU), which was synthesized from poly(tetramethylene glycol), 4,4′‐methylene bis(phenylisocyanate), and 1,4‐butanediol, onto polyester woven fabrics. Water vapor permeability and mechanical properties were investigated as a function of PU hard‐segment content or polymer concentration of the coating solution. Water vapor permeability of PU‐coated fabrics decreased dramatically with increased concentration of coating solution, whereas only a slight change was observed with the control of PU hard‐segment content. The coated fabric showed the clear appearance of a nonporous PU surface according to SEM measurements. Attainment of high water permeability in PU‐coated fabrics is considered to arise from the smart permeability characteristics of PU. Mechanical properties of coated fabrics, although there was some variation depending on the concentration of coating solution, were primarily affected by PU hard‐segment content. Fabrics coated with PU hard‐segment content of 40% showed the lowest breaking stress and modulus as well as the highest breaking elongation, which could be interpreted in terms of the dependency of mechanical properties of coated fabrics on PU hard‐segment content and the yarn mobility arising from a difference in penetrating degree of coating solution into the fabric. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2812–2816, 2004     

PCL–PEG–PCL triblock ester–ether copolydiol-based waterborne polyurethane. II. Effect of NCO/OH mole ratio and DMPA content on the physical properties

This article was focused on the effects of the NCO/OH molar ratio and 2,2-bis(hydroxyl methyl) propionic acid (DMPA) content during prepolymerization on the physical properties of synthesized waterborne polyurethane (WBPU) by using the polycaprolactone–poly(ethyl glycol)–polycaprolactone triblock copolydiol (PCL–PEG–PCL) as the soft segment. The results showed that the particle size of the WBPUs' dispersion decreased with a decreasing NCO/OH molar ratio or increasing DMPA content. Regarding thermal and mechanical properties, the WBPUs had a higher T_g's and lower T_m's and a higher breaking stress and a lower breaking strain of film with the NCO/OH molar ratio or DMPA content increase. The increasing NCO/OH molar ratio was advantageous to the water vapor permeability (WVP)-breaking stress balance, but the effect of the DMPA content on the WVP was not significant. The WBPU with PCL–PEG–PCL as the soft segment had a smaller particle size in dispersion and a better WVP-breaking stress balance than those of WBPU with the blending PCL and PEG as the soft segment. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1301–1311, 1998     

Tensile and elastic properties of thermoplastic elastomers based on PTMO and tetra-amide units

The tensile and elastic properties of melt spun threads of segmented copolymers based on T6T6T-dimethyl (5-16 wt%) and PTMO₁₀₀₀/DMT of different lengths (3000-10,000 g/mol) are very good. Stress-strain measurements show that extruded threads of these polymers have high fracture strains (>1000%) and little strain hardening. The modulus and yield stress increase with increasing T6T6T content. The modulus decreases with increasing drawing-strain as a result of the breaking up of the crystalline network (strain softening). The compression set and tensile set increase with increasing T6T6T content and are low. The uniformity of T6T6T has little influence on the properties. At a soft segment length of 6000 g/mol a fibre with a tensile set of 5%, flow temperature of 200 °C and rubber modulus of 7 MPa is feasible, which can compete with commercial materials.     

Dynamic mechanical behavior and structure of polyurethaneimides

Dynamic mechanical behavior and X-ray diffraction of two series of segmented polyurethaneimides (PUI) prepared either from poly(ethylene adipate) glycol (PEA), pyromellitic dianhydride (PMDA) and 4,4′-diphenylmethane diisocyanate (MDI), or from PEA, PMDA, and a mixture of 2,4- and 2,6-tolylene diisocyanate (TDI) were studied. All samples have a two-phase structure of the soft polyester (PE) phase and hard polyimide (PI) phase. PI microdomains containing MDI units are semicrystalline, whereas those with TDI are crystalline only at highest contents of TDI. The storage modulus E′ increases with increasing fraction of the hard phase. The MDI-containing hard phase has a stronger effect on E′ and also makes the plateau on the dependence of E′ on temperature more pronounced.     

Polyurethanes containing a crystalline polyol and semiflexible urethane segments

Ultradrawing semicrystalline polymers is an intriguing approach to develop stiff, strong, and tough polymeric fibers. In the research field of polyurethane copolymer elastomers the term “soft segment” usually refers to the medium molecular weight glycol while the term “hard segment” stands for the urethane rich or isocyanate‐short glycol segments. Here we investigate the influence of semiflexible segment content in the urethane rich phase on the mechanical properties and morphology of polyurethanes synthesized with a crystalline polyol as a “soft” segment. Materials with lower semiflexible urethane segment content developed stiffer and stronger materials upon drawing. This was related to greater soft segment crystallization along the draw direction. Materials with a higher fraction of semiflexible urethane segments were more elastic (higher yield strains and strengths) but exhibited more brittle‐like fracture. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41281.     

Properties of polyisobutylene-polyurethane block copolymers: I. Macroglycols from ozonolysis of isobutylene-isoprene copolymer

The properties of a series of polyisobutylene (PIB) based polyurethanes were studied and compared to those reported in the literature for polyether, polyester, and polybutadiene-based polyurethanes. Good phase separation was reflected in the invariance of the soft segment T_n with increasing hard segment content. Increasing hard segment content resulted in larger domains, higher modulus and lower ultimate elongation. The modulus above the soft segment T_n was higher than that previously reported for polyurethanes of similar hard segment contant; improved phase separation and short contour lengths of the PIB chains were cited as possible causes of this behavior. Stress-strain data indicated a change from isolated to interconnected domain morphology with incerasing hard segment contant. Generally similar trends were seen for all types of urethanes. The overall properties of polybutadiene polyurethanes were closest to those of the polyisobutylene polyurethanes studied. The properties of both of these systems were suggested to suffer from significant synthesis problems in urethane formation due to the incompatibility of the nonpolar hydrocarbon soft segment and the polar diol chain extender. Preliminary environmental tests indicated that polyisobutylene based materials exhibit improved hydrolytic stability and reduced moisture permeability compared to polyether and polyester polyurethanes and greater oxidative stability compared to polybutadiene based materials.     

IPDI基水性聚氨酯弹性膜的合成与性能

以聚氧化丙烯二醇(PPG)和异佛尔酮二异氰酸酯(IPDI)为软硬段,二羟甲基丙酸(DM-PA)为亲水扩链剂合成了水性聚氨酯(WPU),探讨了DMPA含量、nNCO/nOH、小分子扩链剂类型和软段相对分子质量及配比对WPU弹性膜耐水性和力学性能的影响。结果表明,当DMPA质量分数为7%,R值为3.0左右,并使用醇类扩链剂时能使WPU弹性膜获得较低模量和足够的伸长率,再通过添加适当外加交联剂提升强度,降低其吸水性,最终可制得低模量、适当拉伸强度和伸长率的WPU膜,应用于手套等弹性膜类制品。