硬段含量对水性聚氨酯性能的影响

以聚酯多元醇和异佛尔酮二异氰酸酯(IPDI)为主要原料，引入亲水单体二羟甲基丙酸(DMPA)，按不同配比合成了系列聚氨酯乳液。考察了硬段含量对乳液粒径、表观黏度、膜吸水性、硬度、力学性能的影响，并通过动态力学性能测试(DMA)研究了软段和硬段的玻璃化转变温度。结果表明：提高-NCP/-0H物质的量之比、DMPA用量均使聚氨酯中软段的玻璃化温度Tg(s)降低，硬段的玻璃化温度Tg(h)升高，△T值增加，软硬段相分离程度增加。随乙二胺用量的增加，会使软段玻璃化转变温度Tg(s)移向高温，软硬段相分离程度降低；硬段含量提高，胶膜硬度增加，拉伸强度增加，胶膜耐水性降低。     

BAMO-GAP基ETPE的合成与性能研究

以3,3′-二叠氮甲基氧丁环均聚物(PBAMO)和4,4′-二苯基甲烷二异氰酸酯(MDI)为硬段,聚叠氮缩水甘油醚(GAP)为软段,1,4-丁二醇(BDO)为扩链剂,采用预聚体法合成了BAMO-GAP基含能热塑性弹性体(ETPE);采用FT-IR、NMR方法对ETPE的结构进行了表征;研究了合成条件对ETPE的力学性能、相对分子质量、玻璃化转变温度以及软化点的影响。结果表明,合成的ETPE符合预期结构;异氰酸酯指数(R)大于1时生成交联体。n(PBAMO)∶n(GAP)为0.35∶0.65时,ETPE胶片的力学性能最佳;随着n(PBAMO+GAP)∶n(MDI)∶n(BDO)中BDO比例的增大,ETPE的相对分子质量得到提高,改善了胶片的力学性能,PBAMO相对含量的提高导致玻璃化转变温度升高;软化点随n(PBAMO+GAP)∶n(MDI)∶n(BDO)中BDO所占比例、R值、n(PBAMO)∶n(GAP)的增大而升高。     

聚酯软段对聚氨酯弹性体力学性能影响的研究

以不同结构聚酯多元醇(PEA、PEPA、PBA、PCL)为软段,4,4′-二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)为硬段采用预聚法合成了聚氨酯(PU)弹性体。讨论了MDI/BDO体系中软段种类、相对分子质量、预聚体NCO含量及催化剂对PU弹性体力学性能的影响,并与TDI/MOCA体系进行比较。结果表明,当软段相对分子质量相同时,以PBA为原料合成的PU弹性体硬度最高,弹性体的拉伸强度、伸长率和冲击弹性均随软段相对分子质量的增加而增加;提高预聚体NCO含量可使PU弹性体的硬度、撕裂强度和300%模量增加;但加入催化剂的PU弹性体,其拉伸强度下降16.6%～20.1%;MDI/BDO体系PU弹性体的撕裂强度和冲击弹性较高,TDI/MOCA体系PU弹性体的拉伸强度较好、永久变形较低。     

MDI异构体对聚氨酯弹性体微观结构和性能的影响

以聚氧化丙烯二醇(DL-2000)为软段,不同2,4′-异构体含量的二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)为硬段,采用预聚法合成了不同异构体含量的MDI型聚氨酯弹性体。采用FT-IR、DSC和DMA等分析手段对其结构和性能进行了表征。结果表明,随着2,4′-MDI异构体含量的增加,硬段间的氢键结合化程度降低,硬段区聚集结晶的能力也不断下降,硬段趋于均匀分散在连续相软段区中,两相相容性增加,聚氨酯弹性体的T和tanδ大幅度提高。     

聚碳酸酯二醇型水性聚氨酯胶粘剂的研究

采用预聚体分散法制备了一系列聚碳酸酯二醇(PCDL)型水性聚氨酯(WPU)胶粘剂,并借助傅里叶变换红外光谱(FT-IR)法来跟踪预聚体的合成过程,同时还考察了该WPU胶粘剂的粘度、热稳定性和初粘强度等性能。实验结果表明,PCDL的结构和相对分子质量对该WPU胶粘剂的性能影响很大;以PCDLT-6002为原料制备的WPU胶粘剂,其粘度最低(175 mPa.s)、热稳定性最好、软链段玻璃化转变温度(Tg)最低(-33.97℃)、有软段结晶熔融峰且初粘强度最高(81N/25 mm,此时活化温度为70℃)。     

软段对热塑性聚氨酯弹性体结构及性能的影响

以二苯基甲烷-4,4′-二异氰酸酯(MDI)和扩链剂1,4-丁二醇(BDO)为聚氨酯弹性体硬段(控制硬段质量分数32%),以实验室自制聚己二酸乙二醇酯二醇(PEA)和聚己二酸乙二醇丙二醇酯二醇(PEPA)为软段,经预聚体法合成不同结构的热塑性聚氨酯弹性体(TPU)。研究了弹性体软段部分对其硬度、力学性能和结晶性能的影响。结果表明,控制热塑性聚氨酯弹性体硬段部分不变,改变软段,材料硬度变化不大;软段聚酯二元醇随其相对分子质量的增加,TPU力学性能和结晶性能均增强;研究不同PG含量的软段PEPA-TPU发现,当PG质量分数为10%时,TPU力学性能与结晶性能最好。     

PEG/PCL基复合软段降解型PUF力学与动态力学特性研究

采用一步法制备了聚乙二醇/聚己内酯（PEG/PCL）复合软段聚氨酯泡沫塑料（PUF）,研究了PEG/PCL复合软段配比、软段相对分子质量等对PUF力学性能和动态力学性能的影响。结果表明,无论是采用相对分子质量为400还是相对分子质量为1000的PEG与PCL-210N复合,随软段中PCL含量的增大,材料的拉伸强度、断裂伸长率、定应变应力均提高;随着PEG相对分子质量的增大,材料的断裂伸长率提高,拉伸强度、定应变应力降低;玻璃化转变温度（Tg）顺序为Tg（PEG400）> Tg（PCL210N）> Tg（PEG1000）。     

平面与弯曲形硬质聚氨酯的形状记忆效果及热／机械性能比较

本文用1,4-苯基二异氰酸酯(PDI)、聚四甲撑二醇(PTMG)和1,4-丁二醇扩链剂合成了一系列形状记忆聚氨酯共聚物,并与4,4′-二苯甲烷二异氰酸酯(MDI)和PTMG合成的形状记忆聚氨酯作了比较,用IR光谱、相转移和机械性能测试等方法对二者的相同点和不同点作了对比研究,测试温度为玻璃化转换温度(Tg)±20℃。结果表明,Tg随着(PDI或MDI)含量的增大而增大,当硬段含量相同时,这两种共聚物的Tg相同,而且,用动力机械分析测定了tanδ损失和模量损失,并研究了振动和冲击吸收能力。     

PBA/MDI体系聚氨酯弹性体力学性能的研究

采用二步法以聚己二酸丁二醇酯(PBA)、4,4-′二苯基甲烷二异氰酸酯(MDI)和二元醇1,4-丁二醇(BDO)或混合扩链剂(二元醇和三元醇)合成了聚氨酯(PU)弹性体。研究了软段相对分子质量、预聚体-NCO质量分数和扩链剂对聚氨酯弹性体力学性能的影响。实验结果表明:PBA相对分子质量大,PU断裂伸长率和冲击弹性好;PU硬度、撕裂强度和模量随预聚体-NCO相对质量分数增加而增加;弹性体的交联密度过高,硬度和撕裂强度下降。     

可再生多元醇蓖麻油基聚氨酯灌封胶的制备与性能研究

以蓖麻油、聚醚多元醇(PPG)、液化MDI为主要原料,以1,2-丙二醇(PDO)为扩链剂,采用预聚体法合成制备出聚氨酯灌封胶,讨论了异氰酸酯指数R、硬段质量分数等对聚氨酯灌封胶性能的影响。结果表明:随硬段质量分数、R值的增加,材料的硬度、拉伸强度上升,而断裂伸长率降低;聚氨酯耐水解性(吸水率≤0.366%)好,起始分解温度(277℃)高,热稳定性好;阻尼性能随R值增加而减少,玻璃化转变温度向高温方向移动,且材料软硬段相容性较好。     

不同原料对合成PUR弹性体性能的影响

采用相同官能度、不同分子量的聚醚多元醇和甲苯二异氰酸酯(TD I)及扩链剂反应合成了系列聚氨酯(PUR)弹性体,同时对所合成的PUR弹性体进行了表征。结果表明,聚醚多元醇的相对分子质量对PUR弹性体的性能有较大影响,相对分子质量越大,柔性链段含量就越多,弹性体的拉伸强度、断裂强度和硬度就减小,断裂伸长率则相对提高。同时也进一步证明了软硬链段之间的均匀分布和较强的相互作用更有利于弹性体力学性能的提高。     

New linear polyurethaneureas based on polyoxytetramethylene,aliphatic diisocyanates,and aromatic diamines

New polyurethaneureas have been synthesized with α-ω hydroxylated polyoxytetramethylene, aliphatic diisocyanates and nonhalogenated aromatic diamines. Four series of PUR have been studied by varying the PTMO molecular weight, the stoichiometry, the nature of the aliphatic diisocyanate, and the steric hindrance of the aromatic diamine. Quantitative evaluation of the degree of phase separation was obtained by DSC. An estimation of the dispersed soft segments outside the soft phase could thus be made. In addition to DSC, dynamic mechanical properties, were obtained for the four series of PUR over a wide temperature range. The hard segments in the PUR chains are amorphous and their high temperature behavior depends only on the strength of interactions in the amorphous state. Finally, stress-strain measurements were carried out on a few samples, and a wide range of tensile properties has been observed.     

原位聚合法制备聚氨酯/蒙脱土复合材料研究

采用原位聚合方法制备了蒙脱土( MMT)在聚氨酯(PUR)基体内呈不同分散状态的PUR/MMT复合材料.PUR预聚反应结束后加入MMT制备的PUR/MMT,MMT片层间距增大,基本以插层状态存在;利用异氰酸酯与MMT上的羟基官能团反应,使部分PUR分子链的硬段部分连接在MMT片层之上,可以使MMT片层在PUR基体内几乎...     

PEG对生物可降解聚氨酯性能影响的研究

以不同相对分子质量的聚乙二醇(PEG)为引发剂,通过开环聚合引发丙交酯和己内酯单体合成聚己内酯–丙交酯–聚乙二醇(PCLA–PEG)的共聚物;用六亚甲基二异氰酸酯(HDI)对合成的共聚物进行封端,并进行扩链反应制备一系列PEG含量不同的生物可降解聚氨酯。通过红外以及DSC研究了PEG含量对聚氨酯材料结构的影响,发现采用相对分子质量较高的PEG制备的材料,其软硬段相分离程度较高;另外对样品的力学性能、亲水性及降解性进行了测试,发现PEG含量增加,样品的力学性能下降,亲水性能提高,降解速度加快。     

聚乙二醇对混合嵌段聚氨酯透湿性能的影响

综合考虑聚酯型聚氨酯和聚醚型聚氨酯的特点,以聚己二酸丁二醇酯(PBAG)和聚乙二醇(PEG)混合作为软段,采用溶液预聚法制备了聚酯-聚醚混合型聚氨酯。考察了混合软段中PEG摩尔分数以及PEG相对分子质量对聚氨酯薄膜的表面接触角、吸水率、透湿率及力学性能的影响。结果表明,随着PEG摩尔分数的增大和PEG相对分子质量的增大,薄膜的接触角和拉伸强度降低,吸水率、透湿率增大。当PEG摩尔分数从0.28增加到0.71时,薄膜接触角从75.8°降低至63.5°,吸水率从25.7%增加到106.1%,透湿率从1226g/(m2·24h)增加到3408g/(m2·24h);PEG相对分子质量从1000增加到10000时,薄膜接触角从80.5°降到55.7°,吸水率从4.5%增加到356.4%,透湿率从733g/(m2·24h)增加到3577g/(m2.24h)。     

聚醚酰胺嵌段共聚物的合成及表征

采用熔融缩聚法合成了聚酰胺(PA)6/聚四氢呋喃(PTEMG)嵌段共聚物,研究了PA6、PTEMG链段的相对分子质量、含量对嵌段共聚物热性能的影响,通过傅立叶变换红外光谱、核磁共振、差示扫描量热、热重测试等对产物进行分析.结果表明,嵌段共聚物以羧基封端,当PA6、PTEMG链段相对分子质量分别为2 000、1 000时,共聚物的分子序列长度最长,相对分子质量最大;PTEMG链段相对分子质量越小,共聚物的熔点越低;PTEMG链段相对分子质量相同时,随PA6链段相对分子质量的增加,熔点升高;嵌段共聚物中PA6组分的熔融温度范围随着PTEMG含量的增加而逐步变宽;共聚物具有较高的热分解活化能.     

基于两种双硫键自修复聚氨酯制备及性能

以异佛尔酮二异氰酸酯(IPDI)和双(2–羟基乙基)二硫醚(DTBO)为硬段,聚四氢呋喃(PTMG)为软段,β–巯基乙醇(ME)为封端剂,制备巯基封端且含双硫键的聚氨酯(PUR)预聚物,利用巯基易氧化的特点,用H2O2/NaI进行氧化,合成分子链内和分子链端均含有双硫键的自修复交联PUR。采用傅立叶变换红外光谱仪、差示扫描量热仪、热重/差热综合热分析仪和电子拉力试验机等手段,研究了PUR的结构及PTMG与ME的物质的量之比对PUR热性能、力学性能和自修复性能的影响。结果表明,合成的系列交联PUR都具有一定的自修复能力和良好的热性能,当DTBO和PTMG物质的量分数分别为总二元醇的40%和60%时,PUR的拉伸强度达到最大值,为2.6 MPa,在60℃热处理8 h条件的自修复率为80.8%,且该试样经三次自修复后,自修复率仍可达到50.0%。     

Dielectric properties of segmented polytetramethyleneoxide-based polyurethanes

Three series of segmented polyurethanes, based on polytetramethylene oxide (PTMO) soft segments, having molecular weights of 650, 1000, and 2000 and MDI/butane diol hard segments, were synthesized and their dielectric properties examined. The effect of the soft segment length, soft segment concentration (ssc) as structural variables, and frequency and temperature as experimental variables, on relative permittivity and tan δ, were examined. The results were discussed in terms of the structural parameters such as the degree of phase separation and soft segment phase state. It was found that both soft segment length and ssc strongly affect dielectric behavior.     

Thermal stability of polyurethane elastomers before and after UV irradiation

In this work, we investigated the thermal degradation behavior of segmented polyurethane (PUR) elastomers before and after UV irradiation. The thermal degradation of PUR elastomers was studied over the temperature range of 25–600°C in an atmosphere of nitrogen using thermal gravimetric analysis (TGA). Four series of PUR elastomers derived from poly(oxytetramethylene)glycol (PTMO) of 1000 and 2000 molecular weight and poly(caprolactone glycol) (PCL) of 1250 molecular weight, 4,4′‐diphenylmethane diisocyanate (MDI), and 4,4′‐dicyclohexylmethane diisocyanate (H₁₂MDI) and 1,4‐butanediol as an chain extender were synthesized by the prepolymer method. The derivative thermogravimetric (DTG) peaks observed in the experiments indicated that PUR elastomers degraded through two steps. We attributed the first step to degradation of the hard segment. The second degradation step could be ascribed to degradation of the soft segment. We found that the PUR elastomers based on poly(ester polyol) and aromatic diisocyanate exhibit better thermal stability than that of PUR elastomers based on the poly(ether polyol) soft segment in both steps of degradation. The thermal degradation is more prevalent in PUR elastomers based on cycloaliphatic diisocyanate. The higher values of the temperature of initial decomposition (Tⁱ) indicate a higher thermal stability of UV‐exposed elastomers on the beginning of degradation. This may be due to the formation of a crosslinking structure in the presence of UV irradiation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 864–873, 2001     

Toughening of epoxy resins modified with polyetherester block copolymers: the influence of modifier molecular architecture on mechanical properties

Thermoplastic elastomers based on polyetheresters with polyoxytetramethylene soft segments and poly(hexamethyleneterephthalate) hard segments were used to toughen anhydride‐cured epoxy resins. The ratio between hard and soft segments and the crystallinity of the hard segments prepared by incorporating poly(hexamethyleneisophthalate) in the block copolymer were varied in order to examine the effect of the modifier's molecular architecture on morphology and mechanical properties of the resin, such as toughness, strength, and stiffness. The experimental data show that segmented polyetheresters are suitable toughening agents for epoxies. The compatibility between resin and toughener and also the mechanical properties of the modified resin depend on the ratio between the hard and soft segments. Epoxy resins blended with 10 wt % of the polyetherester exhibit an increase in toughness by 50–150%, while strength and modulus decrease by 20% or less. An optimal phase adhesion at levels between 70 and 85 wt % of soft segments in the modifier results in a maximum of toughness enhancement (by about 150%) of the resin accompanied with only a slight drop in strength and stiffness (by about 15%). The glass transition temperature is only slightly affected. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 623–634, 2000