Preparation and characterization of waterborne poly(urethane urea) with well‐defined hard segments

A series of polyester‐based poly(urethane urea) (PUU) aqueous dispersions with well‐defined hard segments were prepared from polyester polyol, 4,4′‐diphenylmethane diisocyanate, dimethylolpropionic acid, 1,4‐butanediol, isophorone diisocyanate, and ethylenediamine. These anionic‐type aqueous dispersions had good dispersity in water and were stable at the ambient temperature for more than 1 year. For these aqueous dispersions, the particle size decreased as the hard‐segment content increased, and the polydispersity index was very narrow (<1.10). Films prepared with the PUU aqueous dispersions exhibited excellent waterproof performance: the amount of water absorption was as low as 5.0 wt %, and the contact angle of water on the surface of this kind of film was as high as 103° (this led to a hydrophobic surface). The water‐resistant property of these waterborne PUU films could be well correlated with some crystallites and ordered structures of the well‐defined hard segments formed by hydrogen bonding between the urethane/urethane groups and urethane/ester groups, as well as the degree of microphase separation between the hard and soft segments in the PUU systems. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2606–2614, 2005     

Evidences of phase separation in moisture‐cured poly(urethane urea)s by means of temperature modulated differential scanning calorimetry

The degree of phase separation in several moisture‐cured poly(urethane urea)s (PUUs) was studied by FTIR spectroscopy, wide angle X‐ray diffraction (WAXD), and temperature‐modulated differential scanning calorimetry (TMDSC). This latter technique was shown to be particularly useful in analysing the degree of phase separation in PUU polymers. Both phase mixing and phase segregation coexisted in the PUUs and the degree of phase separation increased as the urea hard segment (HS) content in the PUU increased. The maximum solubility of urea HSs into the polyol soft segments (SSs) was achieved for 50 wt % urea HS content in diol‐based PUUs, whereas for triol‐based PUUs the highest solubility between HS and SS was reached for lower urea HS amount. Finally, the higher the urea HS content the higher the extent of phase separation in the PUU. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3034–3045, 2007     

FTIR研究交联聚氨酯脲弹性体的结构对动态性能的影响

用傅立叶变换红外光谱法(FTIR)研究交换PUU的结构指出,化学交联键的存在使得氢键化的NH吸收位置向高波数方向移动,同时羰基区内完全有序的氢键化脲羰基(1642cm-1)吸收较弱,完全有序的氨酯羰基(1693cm-1)吸收谱带观察不到.随着温度的升高,氢键化的NH吸收强度逐渐减弱,谱带吸收位置向高波数方向移动.FTIR结果揭示了交联PUU弹性体内部微相混合程度较线性PUU的高,交联PUU弹性体的回弹性在同温度下小于线性PUU的回弹性,随温度的升高,交联PUU弹性体极性键间的氢键化作用较易破坏,分子的柔顺性增加较快,交联PUU的回弹性增加幅度较大.交联密度越大,回弹性越小,压缩生热越大.硬段含量越高,材料的生热现象越严重.扩链剂的用量增加,对交联PUU的回弹性和压缩生热影响不大,但它显著地改善了PUU的疲劳性能.     

Crystallization and melting behavior of the soft and hard segments in poly(ester-ether)s. I. Ethylene oxide-ethylene terephthalate segmented copolymers

The crystallization and melting behavior of a series of ethylene oxide-ethylene terephthalate (EOET) segmented copolymers with different soft segment molecular weight and hard segment weight content were studied by differential scanning calorimeter (DSC) and polarized microscope. The crystallizability of both the hard and the soft segments became worse than that of the corresponding homopolymers due to the interactions of the different segments. The crystallizability of the soft segments is mainly determined by the soft segment molecular weight, but is affected greatly by the content and the crystallinity of the hard segments. Conversely, the soft segment length and content also have a great effect on the crystallization of the hard segments. However, the melting points of the hard segments are determined by the average hard segment length. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2918–2927, 1999     

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。     

聚乙二醇型聚氨酯软硬段对其相变储热性能的影响

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.     

Poly(urethane–urea) based on functionalized polystyrene with HMDI: Synthesis and characterization

The poly(urethane–urea) (PUU) based on α, Ω, hydroxy terminated polystyrene (OH-PSt-OH), 1,6-hexamethylene diisocyanate (HMDI) and three different diamines (1,2-ethylenediamine (EDA), 1,4-butanediamine (BDA), 1,6-hexamethylene diamine (HMDA)) is prepared by a melt polymerization method. The length of the soft segment is varying from 2000 to 8900 g/mol using HMDI as a chain extender. The inherent viscosity of the polymer is found to be in the range of 0.36–2.0 dL/g suggesting that the polymer is of high molecular weight. FT-IR results conclude that the urea groups form both monodendate and bidendate assemblies. Temperature dependent FT-IR and WAXS data confirm that the crystallinity of the copolymer is very high and depends on the spacer length. DSC data show the peaks for Tg of soft and Tm of hard segments. Depending on the concentration and the type of hard segments, melting temperature of the polymers was varied from 142 °C to 266 °C. The solubility of the polymer in chloroform is depending on the concentration of the hard segment. The TGA data reveal that the polymer shows single stage decomposition cantered around 413 °C.     

用可再生原料合成聚氨酯脲水分散液——成膜后的结构与性能研究

以不同组成的蓖麻油和二官能度聚醚多元醇 (GE 2 10 )等原料合成了聚氨酯脲 (PUU)水分散液 ,研究了蓖麻油 GE 2 10的组成对PUU膜结构与性能的影响 .结果表明 ,由GE 2 10合成的PUU虽软硬段间存在一定的相容性 ,但其中脲羰基的氢键化程度高 ,硬段形成较好的有序结构 ,导致PUU膜具有较高的拉伸强度及断裂伸长率 ,但弹性模量和硬度下降 .在蓖麻油合成的PUU中脲羰基的氢键化程度及硬段有序结构均受到化学交联结构的抑制 ,故PUU膜的拉伸强度和断裂伸长率降低 ,但弹性模量及硬度较高 .由蓖麻油与GE 2 10在一定的组成范围内合成的PUU膜 ,具有优良的综合平衡的力学性能 ,后者与材料的结构形态相符     

Crystallization and melting behavior of the soft and hard segments in poly(ester-ether)s. II. Ethylene oxide-butylene terephthalate segmented copolymers

The crystallization behavior of a series of ethylene oxide-butylene terephthalate (EOBT) segmented copolymers with different soft segment molecular weight and hard segment weight content were examined by differential scanning calorimeter (DSC) and polarized microscope. Combined with the comparison with the crystallization behavior of ethylene oxide-ethylene terephthalate (EOET) segmented copolymers, it can be concluded that the crystallizability of both the soft segments and the hard segments in poly(ester-ether) segmented copolymers is much worse than those of the corresponding homopolymers due to the interactions between the soft and the hard segments. The crystallizability of the soft segments is mainly determined by the soft segment molecular weight, but is weakened by the hard segments. On the other hand, the soft segments have complicated influences on the crystallization of the hard segments. The melting temperatures of the hard segments change monotonically with the average hard segment length, but the corresponding melting enthalpies will reach a maximum at an intermediate soft segment molecular weight. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2928–2940, 1999     

长碳链聚醚酰胺弹性纤维开发及其弹性机理

以长碳链聚酰胺弹性体为原料,通过熔融纺丝技术制备了高性能化新型长碳链聚醚酰胺(LPAE)弹性纤维.该弹性体是以基于生物来源单体的长碳链聚酰胺为硬段,以聚醚为软段,其弹性可通过调节软硬段比例有效调控.测试结果表明,与目前市场上应用广泛的氨纶莱卡(LYCRA)相比,软段含量较高的LPAE纤维具有高断裂伸长,低初始模量的特点;在200%伸长范围内,其弹性回复率与氨纶相当,耐热性优于氨纶.分析得知,LPAE纤维的高弹性源于硬段聚酰胺存在强氢键相互作用且结晶度高,同时硬段充当物理交联点;软段具有良好的柔性,可以发生大变形,这种软硬段交替的嵌段分子链结构形成三维网络.大应变下,LPAE纤维弹性回复率降低是由分子链滑移及软段拉伸诱导结晶共同造成的.     

甲苯二异氰酸酯形成的聚氨酯脲与接枝乙烯基酯树脂互穿网络研究

本文首先通过分子设计技术合成了一系列侧链长度可以控制的接枝乙烯基酯树脂 (接枝VER :BO g VER ,2 0 0 g VER ,390 g VER) ,并用它们与甲苯二异氰酸酯合成的聚氨酯脲 (PUU)形成同步互穿网络(SIN) .通过DSC、SEM等考察了接枝VER的结构对PUU/接枝VERSIN的形态与力学性能的影响 .在PUU/BO g VERSIN中 ,BO g VER网络主要与PUU网络中的硬段相容和互穿 ;对于PUU/ 2 0 0 g VERSIN而言 ,2 0 0 g VER网络与PUU网络中的软段和硬段均有一定的相容性 .由于这两种SIN中两个网络间均有一定的相容性和互穿 ,故这类接枝网络能显著地增强PUU网络 ,使材料的力学性能有较大幅度的提高 .390 g VER网络本身存在的微相分离结构 ,使PUU/ 390 g VERSIN两个网络也存在显著的相分离形态 ,导致390 g VER网络对PUU网络的增强效果并不明显 .     

对苯二甲酸丁二酯-ε-己内酯多嵌段共聚物中硬链段的受限结晶

用差示扫描量热法（DSC）,广角X射线衍射（WAXD）,傅立叶变换红外光谱（FTIR）等技术研究了对苯二甲酸丁二酯-ε-己内酯（PBT—PCL）多嵌段共聚物中硬链段的受限结晶。结果表明,PBT—PCL共聚酯中软硬链段在非晶区的混容性比较好,不同组成的样品均显示出一个玻璃化转变温度;对硬段含量超过50%的共聚酯来说,硬链段可以结晶,而软链段不能结晶;由于硬链段的受限特点,BT硬链段的结晶受软链段的影响和制约,其结晶能力随硬段序列长度的增加而逐渐增大。     

Synthesis and Characterization of Novel Segmented Polyionenes Based on Polydimethylsiloxane Soft Segments

Novel polydimethylsiloxane (PDMS) based polyionenes were synthesized by a modified Menschutkin reaction involving reaction between bromo-terminated PDMS oligomers and various ditertiary amino compounds. In this study, the nature of the hard segment was varied by using various ditertiary amino compounds and in some cases by incorporating chain extenders, while the soft segment content was varied by changing the molecular weight of the PDMS oligomers. The mechanical properties of these materials were found to be dependent on both the nature and amount of the hard segments. These materials also showed distinct evidence of a microphase-separated morphology where under normal conditions, the hard segments formed in what are believed to be cylindrical ion-rich microdomains dispersed randomly in the soft PDMS matrix. When subjected to uniaxial deformation, the ionic cylinders were found to orient along their long axes in the stretch direction.     

Preparation and properties of well‐defined waterborne polyurethaneurea with fluorinated siloxane units in hard or soft segments

Two series of well‐defined polyurethaneurea (PUU) aqueous dispersions consisting of fluorinated siloxane units in the hard and the soft segments, respectively, were prepared from polyester polyol, α,ω‐dihydroxypoly[(3,3,3‐trifluoropropyl) methylsiloxane] (PTFPMS), dimethylolpropionic acid, isophorone diisocyanate, and ethylenediamine. These anionic aqueous dispersions were stable at the ambient temperature for more than 6 months. The experimental results showed that the water‐resistance performance of the PUU films prepared with the insertion of PTFPMS units into the hard segments (HFS series) were better than those prepared with the insertion of PTFPMS units into the soft segments (SFS series). The film prepared from the PUU aqueous dispersion incorporating 5 wt % PTFPMS in the hard segments exhibited the lowest water absorption amount (2.3 wt %) with the contact angle of water on the film surface greater than 90°. In comparison with the PUU film without adding PTFPMS, the waterproof performance and the mechanical properties of both HFS and SFS series were enhanced markedly. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5005–5016, 2007     

Effect of the crosslink density on the morphology and properties of reaction‐injection‐molding poly(urethane urea) elastomers

The effect of the crosslink density on the morphology and properties of reaction‐injection‐molding poly(urethane urea) (PUU) elastomers was investigated. Fourier transform infrared spectroscopy data showed that the linear and crosslinked PUU had entirely different hard‐domain sizes and hard‐segment ordering. A study of the morphology indicated that an increase in the crosslink density increased microphase mixing. Differential scanning calorimetry studies indicated that the hard‐segment initial glass‐transition temperature was independent of the crosslink density. The glass‐transition temperature of the soft segment was highest when the network was perfect. The tensile‐strength behavior showed that the mechanical properties of PUU reached a maximum when the network was perfect. The increase in the resilience of the crosslinked PUU elastomer was higher than that of the linear PUU elastomer with an increase in temperature, and the reduction of the hardness of the former was also higher than that of the latter. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1126–1131, 2004     

具有明确硬段结构的水性聚氨酯脲的研究

通过逐步反应由4,4′-二苯基甲烷二异氰酸酯、2,2-二羟甲基丙酸和1,4-丁二醇,合成了结构明确的硬段模型化合物.通过13C NMR对其序列结构进行了表征,并通过FTIR、DSC和WAXD对其形态结构进行了研究.进一步制备了具有这类规整结构硬段的水性聚氨酯脲,初步考察了水分散液及其成膜后的性能.实验结果表明,这类聚氨酯脲水分散液的粒径小于110nm,在室温下贮存期大于一年,成膜后具有优异的耐水性能以及表面疏水性能.     

Preparation and Pervaporation Performances of PEA‐based Polyurethaneurea and Polyurethaneimide Membranes to Benzene/Cyclohexane Mixture

Pervaporation is promising in the separation of benzene/cyclohexane mixture for the petrochemical industry. Two kinds of pervaporation membrane materials, including PEA‐based polyurethaneurea (PUU) and polyurethaneimide (PUI), were successfully synthesized from the same soft segment of poly(ethylene adipate)diol (PEA) and different hard segments via a two‐step method. The hard segment of PUU was prepared from toluene diisocyanate (TDI) and 4,4′‐diaminodiphenyl methane (MDA), while that of PUI was from 4,4′‐methylene‐bis(phenylisocyanate) (MDI) and pyromellitic dianhydride (PMDA). The structures and properties of PUU and PUI were characterized by means of FT‐IR, DSC and TGA. During the pervaporation experiment, the PUI membranes had a flux of 12.13 kg µm m^?2 h^?1 and separation factor of 8.25, while the PUU membranes had a flux of 26.35 kg µm m^?2 h^?1 and separation factor of 6.29 for 50 wt% benzene in the benzene/cyclohexane mixture at 40°C. The effects of the structures of hard segments on pervaporation performances were discussed. The investigation of the relationship in molecular structure and PV performances will be helpful for the choice and design of membrane materials in the separation of benzene/cyclohexane mixture.     

Calorimetric and Dielectric Study of the Segmented Biodegradable Poly(ester‐urethane)s Based on Bacterial Poly[(R)‐3‐hydroxybutyrate]

Two series of segmented poly(ester‐urethane)s were synthesized from bacterial poly[(R)‐3‐hydroxybutyrate]‐diol (PHB‐diol), as hard segments, and either poly(ε‐caprolactone)‐diol (PCL‐diol) or poly(butylene adipate)‐diol (PBA‐diol), as soft segments, using 1,6‐hexamethylene diisocyanate as a chain extender. The hard‐segment content varied from 0 to 50 wt.‐%. These materials were characterized using ¹H NMR spectroscopy and GPC. The polymers obtained were investigated calorimetrically and dielectrically. DSC showed that the T_g of either the PCL or PBA soft segments are shifted to higher temperatures with increasing PHB hard‐segment content, revealing that either the PCL or PBA are mixed with small amounts of PHB in the amorphous domains. The results also showed that the crystallization of soft or hard segments was physically constrained by the microstructure of the other crystalline phase, which results in a decrease in the degree of crystallinity of either the soft or hard segments upon increase of the other component. The dielectric spectra of poly(ester‐urethane)s, based on PCL and PHB, showed two primary relaxation processes, designated as α_S and α_H, which correspond to glass–rubber transitions of PCL soft and PHB hard segments, respectively. Whereas in the case of other poly(ester‐urethane)s, derived from PBA and PHB, only one relaxation process was observed, which broadens and shifts to higher temperature with increasing PHB hard‐segment content. It was concluded from these results that our investigated materials exhibit micro‐phase separation of the hard and soft segments in the amorphous domains.     

Preparation and properties of waterborne polyurethaneurea consisting of fluorinated siloxane units

A series of polyurethaneurea (PUU) aqueous dispersions were prepared via a prepolymer process from polyester polyol, α,ω‐dihydroxypoly[(3,3,3‐trifluoropropyl) methylsiloxane] (PTFPMS), dimethylolpropionic acid, isophorone diisocyanate, and ethylenediamine. These anionic‐type aqueous dispersions were stable at the ambient temperature for more than 6 months, with particle sizes ranging from 69 to 127 nm. For these aqueous dispersions, the surface tension decreased with increasing PTFPMS content, but the particle size increased with a maximum value. The film prepared from the PUU aqueous dispersion consisting of 5 wt % PTFPMS (APU‐FS‐5) exhibited excellent waterproof performance. Furthermore, the tensile strength of the APU‐FS‐5 film increased nearly 3 times compared with that of the PUU film without PTFPMS, whereas the elongation at break only decreased a little; this indicated that the water‐resistant and mechanical properties could be enhanced markedly and simultaneously for the PUU films containing both silicon and fluorine groups. The experimental results showed a high degree of hydrogen bonding for urea groups and an increased microphase‐separation degree between the hard and soft segments in the PTFPMS‐modified system, which resulted in the excellent mechanical properties of these films. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3365–3373, 2006     

New type of thermoplastic multiblock elastomers––poly(ester-block-amide)s––based on oligoamide 12 and oligoester prepared from dimerized fatty acid

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.