不同硬段含量嵌段聚脲合成及性质的研究

用两步溶液聚合法合成了硬段含量不同的一系列热塑性嵌段聚脲.研究了影响反应的各种因素.所得聚脲是线性和无定形的.用DSC和DMS法初步研究了这些聚脲的性质,随硬段含量增加.聚脲从软弹性体转变为高模量的硬塑料.     

聚氰丙基甲基硅氧烷-聚脲嵌段共聚物的结构和性能

本文以氨丙基封端聚(氰丙基,甲基)硅氧烷(CH_2)_3CN:CH_3=1:5),MDI和EDA为原料,采用DMAC单一溶剂合成了一系列高软段分子量(Mn=3000～9000)和高硬段含量(7～30%wt)的多嵌段共聚物。产物为透明热塑性弹性体,具有良好的成膜性能和宽阔的使用温区,其杨氏模量比相应的聚二甲基硅氧烷-聚脲显著提高。通过FT-IR,WAXD,DSC,DMA等证明其硬段为近程有序结构,氰丙基与聚脲硬段有氢键作用,这一作用力使两相相溶性提高,“界面厚度”增加。氰丙基的引入和硬段含量的增加对材料相结构和力学性能有显著影响。     

CAMDA扩链聚氨酯脲的硬段对形态与性能的影响

由红外光谱、核磁共振及质谱分析证实了所合成的3-氯-3’-甲氧基-4,4’-二氨基二苯基甲烷(CAMDA)具有预期的化学结构.用RIM方法制成的CAMDA基聚氨酯脲(PUU)性能接近于DETDA扩链的PUU.用快速手工浇注法制备了一系列由CAMDA扩链的不同硬段含量的PUU样品.采用DSC、SEM观察了硬段含量由10％增加到45％PUU形态的变化,并测量了力学性能.实验结果表明:随着硬段含量增加,PUU的形态由平行间隔的软、硬链段富集区经相互穿叉的软、硬段富集区,进一步聚集成硬链段富集球状超级结构,强度亦相应提高.     

不同硬段含量脂肪族聚脲的结构与性能研究

通过端氨基聚醚、异佛尔酮二异氰酸酯和异佛尔酮二胺反应 ,合成了一系列不同硬段含量的脂肪族聚脲 ,并用DSC和FTIR等考察了硬段含量对聚脲的微观结构与力学性能的影响 .研究结果表明 ,聚脲呈现部分微观分相的形态 ,随硬段含量增加 ,聚脲中软段和硬段间的相容性提高 ,脲羰基的氢键化程度增加 ,但软段的玻璃化转变温度变化不大 ;此外 ,材料的拉伸强度、撕裂强度和硬度等也随着硬段含量的增加而显著提高 .     

嵌段聚酯型聚脲氨酯弹性体的热转变研究

用示差扫描量热法(DSC)研究了基于二苯基甲烷二异氰酸酯(MDI)、乙二胺(ED)和聚己二酸丁二醇酯(PBA)(M.W.1975和M.W.1228)两系列嵌段聚酯型聚脲氨酯(PUU)弹性体,并考察了这些材料在不同退火条件下软段结晶的热变化。结果表明:在这些弹性体中,PBA 1975系列具有比PBA1228系列更低的软段玻璃化温度,说明前者的相分离较好.软段T_(gs)和硬段T_(gh)对硬段含量的变化不敏感.退火样品的DSC结果表明:软段结晶具有两个吸热峰,提出在软段相中存在两种晶型(P_l和P_h)的假设,分析了两种晶型产生的原因.     

嵌段聚酯型聚脲氨酯弹性体的动态力学性能

聚氨酯(PU)的微区结构和宏观力学性能之间的关系是PU的一个重要课题。本文用动态力学方法对基于4,4'-二苯基甲烷二异氰酸酯(MDI),乙二胺(ED)和聚已二酸丁二醇酯(PBA)的嵌段聚酯型聚脲氨酯(PUU)弹性体进行了研究,探讨了不同软段分子量和硬段     

硬链段浓度对RIM交联聚氨酯结构和性能的影响

用l-MDI/1,4-BDO/PPO-EO快反应体系,考察硬段浓度对聚氨酯结构与性能的影响。发现样品的交联度、模量和抗张强度随硬段浓度增加而提高,交联趋向均匀,断裂伸长率在浓度30％处出现最大值。ATR-FTIR和DSC分析表明,微相分离程度随硬段浓度增大而降低。     

聚硅氧烷聚脲嵌段共聚物的TEM及SAXS研究

采用透射电子显微镜与小角X光散射分别研究了不同软、硬段分子量及软段极性对聚硅氧烷聚脲多嵌段共聚体系微相结构的影响。结果表明,增加软段分子量及硬段含量有利于聚硅氧烷与聚脲的相分离。将极性氰丙基引入聚硅氧烷后两相混合度明显改善,同时聚脲硬段粒径减小并趋于均一。在聚氰丙基甲基硅氧烷基体中增加聚脲含量及其分子量,则两相界面厚度也随之增大。     

长软链段对苯二甲酸乙二酯-环氧乙烷多嵌段共聚物的组成不均一性研究

合成了不同软链段长度和不同硬链段含量的系列对苯二甲酸乙二酯－环氧乙烷(PET-PEO)多嵌段共聚物,用NMR质子港测定了硬链段含量,对部分溶于氯仿的PET－PEO多嵌段共聚物进行了分离,并分别测定其氯仿可溶物和不溶物的硬链段含量、熔融热谱和热结晶谱.揭示了PET－PEO多嵌段共聚物的组成不均一性及其对软镇段长度和硬链段含量的依赖性,进而用DSC热谱证明了软链段和硬链段的结晶能力与PET－PEO多嵌段共聚物组成不均一性密切相关.     

扩链剂对脂肪族聚氨酯脲和聚脲弹性体结构与性能的影响

用异佛尔酮二胺(IPDA)、乙二胺(EDA)和己二胺(HDA)三种扩链剂合成了不同结构的脂肪族聚氨酯脲和聚脲, 并考察了扩链剂对聚氨酯脲和聚脲形态结构与性能的影响. 研究结果表明, 与EDA和HDA扩链的聚氨酯脲和聚脲相比, IPDA扩链的聚氨酯脲和聚脲中脲羰基的氢键化程度较低, 软段和硬段间的相混合程度较好; 同时它们具有更好的拉伸强度、硬度和撕裂强度, 但断裂伸长率较低. EDA和HDA扩链的聚氨酯脲和聚脲相比, 两者性能相差不大. 聚氨酯脲的脲羰基较完善氢键化程度以及整个氢键化程度都比聚脲的要低, 同时聚氨酯脲的吸水率也较低.     

Microphase separation in RIM polyureas as studied by solid-state NMR

The microphase separation (MPS) in polyureas based on methylene diphenyl diisocyanate (MDI) hard segment, diethyltoluenediamine chain extender, and amino-terminated polypropylene glycol soft segment prepared by reaction injection molding (RIM) was studied by advanced solid-state NMR spectroscopy. Incomplete microphase separation leads to the presence of mobilized hard segments dispersed in the soft segment domains as well as immobilized soft segments residing in the hard domains. This is detected by ¹H-NMR spectra recorded under spinning at the magic angle (MAS) as well as two-dimensional wide-line separation (WISE) NMR spectra. The sizes of the various domains as well as the interfaces between them are quantified by spin diffusion measurements. In this way the impact of annealing, method of polymerization, and hard segment content on MPS is studied. Whereas annealing at temperatures up to 170°C results in improving the MPS, major changes are observed after annealing at higher temperatures (190°C), where the system changes from “soft-in-hard” to “hard-in-soft” behavior. The MPS decreases with increasing hard segment content. The highest MPS is observed for solution polymerized samples. The various NMR experiments clearly reveal the nonequilibrium nature of RIM systems. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 693–703, 1998     

Novel Urea-Siloxane Polymers as Gelling Agents for Silicone Fluids: Influence of the Hard Segment

A series of polyureas were synthesized from amino terminated polydimethylsiloxane oligomers, diamine comonomers, and various diisocyanates. These polymers were characterized by nuclear magnetic resonance (NMR), infrared (IR) spectroscopy, and size exclusion chromatography (SEC). The gelation behavior in silicone fluids such as dimethylcyclosiloxanes was investigated. The influence of the structure of the hard segment on the gelation properties was evaluated.     

Novel Urea-Siloxane Polymers as Gelling Agents for Silicone Fluids: Influence of the Hard Segment

Summary. A series of polyureas were synthesized from amino terminated polydimethylsiloxane oligomers, diamine comonomers, and various diisocyanates. These polymers were characterized by nuclear magnetic resonance (NMR), infrared (IR) spectroscopy, and size exclusion chromatography (SEC). The gelation behavior in silicone fluids such as dimethylcyclosiloxanes was investigated. The influence of the structure of the hard segment on the gelation properties was evaluated.     

Novel urea-siloxane polymers as gelling agents for silicone fluids

A series of polyureas were synthesized from amino terminated polydimethylsiloxane oligomers of different molecular weight and various diisocyanates. These polymers were characterized by nuclear magnetic resonance (NMR), infrared (IR) spectroscopy and size exclusion chromatography (SEC). The formation of hydrogen bonding of the urea segments was investigated by temperature dependent IR-spectroscopy. The gelation behavior in silicone fluids such as dimethylcyclosiloxanes was investigated. The influence of the structure of the hard and the soft segment on the gelation properties was evaluated.     

聚环氧氯丙烷氨酯阻尼材料的阻尼性能研究

<正> 一般来讲,聚合物材料的阻尼性能来源于分子链运动带来的内摩擦力以及分子间物理键的破坏与再生,分子链运动所产生的阻尼在聚合物的玻璃化转变温度范围内最为有效。因此具有极性较强、体积较大的一CH_2Cl侧基的环氧氯丙烷聚合物应具有优异的阻尼性能,专利文献[1—2]报道过由多羟基(官能度≥2)聚环氧氯丙烷预聚物为原料制得的聚氨酯泡沫具有良好的阻燃性能,作者在聚环氧氯丙烷氨酯阻尼材料方面进行了尝试。     

Polyisobutylene‐based segmented polyureas. I. Synthesis of hydrolytically and oxidatively stable polyureas

Novel segmented polyurea elastomers containing soft polyisobutylene (PIB) segments were synthesized and characterized. The key ingredient, primary amine‐telechelic PIB oligomers (NH₂‐PIB‐NH₂) with number average molecular weights of 2500 and 6200 g/mol were synthesized. PIB‐based polyureas were prepared by using various aliphatic diisocyanates and diamine chain extenders with hard segment contents between 9.5 and 46.5% by weight. All copolymers displayed microphase morphologies as determined by dynamic mechanical analysis. Tensile strengths of nonchain‐extended and chain‐extended polyureas showed a linear dependence on the urea hard segment content. PIB‐based polyureas prepared with NH₂‐PIB‐NH₂ of M_n = 2500 g/mol, 4,4′‐methylendbis(cyclohexylisocyantate), and 1,6‐diaminohexane containing 45% hard segment exhibited 19.5 MPa tensile strength which rose to 23 MPa upon annealing at 150 °C for 12 h. With increasing hard segment content, elongation at break decreased from ～ 450% to a plateau of 110%. The hydrolytic and oxidative stability of PIB‐based polyureas were unprecedented. Although commercial “oxidatively resistant” thermoplastic polyurethanes degraded severely upon exposure to boiling water or concentrated nitric acid, the experimental polyureas survived without much degradation in properties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 38–48, 2009     

丁苯、丁腈基聚氨酯的形态与性能

用示差扫描量热法 (DSC)、红外分光光度计 (FTIR)和原子力显微镜 (AFM)研究了端羟基聚丁二烯 苯乙烯共聚物 (HTBS)、端羟基聚丁二烯 丙烯腈共聚物 (HTBN)和端羟基聚丁二烯 (HTPB)与甲苯二异氰酸酯、1 ,4 丁二醇构成的溶液法聚二烯烃基聚氨酯 (PU)的形态结构 .结果表明HTPB和HTBS基PU的相分离程度很大 ,而HTBN基PU的相分离程度小 .这可能归因于HTBS软段的极性低 ,不能与硬段形成氢键 ,而HTBN软段中的腈基具有很强的极性 ,且可以与硬段形成氢键作用 ,增加了软硬段间的相容性 ,相分离程度明显降低 .AFM表明HTBN PU随着硬段含量提高 ,表面粗糙度增大 ,由软段为连续相逐渐过渡到双连续结构 .在硬段含量 6 3%时 ,HTBN和HTPB基PU均呈双连续结构 ,而HTBS PU中硬段为连续相 .HTBN PU软段的相区尺寸在1 2nm左右 ,表面粗糙度较大 ,HPBS PU软段的相区尺寸在 1 1nm左右 ,表面粗糙度最小 ,HTPB PU存在 1 4nm和 5 0nm大小不等的软段相区尺寸 .力学性能表明 ,在软段中引入苯乙烯和丙烯腈结构 ,可使聚氨酯抗张强度分别提高 1 5和 2倍 ,模量和断裂伸长率也明显提高