聚（1,3—二氧环庚烷）二醇类聚氨酯的相态结构：软段链结构对聚氨..

用ＦＴＩＲ和ＤＣＳ对聚二醇为软段的聚氨酯的相态结构进行了分析。结果表明：与聚四氢呋喃二元醇类聚氨酯相比，主链中引入甲氧基后，软段相的结晶能力物采上中有序区的均匀程度下降。探讨了软段链结构对聚氨酯相态结构的影响。     

聚甲基丙烯酸胆甾醇酯共聚物的合成、结构与性能研究 Ⅳ.PMACE的相态转变及光学性质

Finkelmann和等人对侧链胆甾型高分子液晶的研究表明,将具有液晶功能的低分子基团,经过一个软段连接到柔性高分子主链上的梳型高分子在一定的温度下可以形成液晶态,调节侧链高分子液晶的分子结构、软段长度,可以改变其相态转变温度及微区形态。前已报导具有不同侧链结构的聚甲基丙烯酸胆甾醇酯共聚物的合成、相态转变及光学性质,本文通过对聚甲基丙烯酸胆甾醇乙烯酯共聚物(PMACE)的液晶态及结晶态的微细结构及相态转变与胆甾侧链含量关系的研究,给出了液晶态的形成条件及结构特征。     

液晶型聚氨酯弹性体的固体高分辨核磁共振研究

采用固体高分辨＾１３Ｃ核磁共振谱以及溶液碳谱、氢谱的方法对以聚四氢呋喃（ＰＴＭＯ）为软段、４，４＇－二苯基甲烷二异氰酸酯（ＭＤＩ）为硬段、４，４＇－二羟已氧基联苯（ＨＢ６）为扩链剂的液晶型聚氨酯弹性体的相态结构、分子运动、氢键相互作用等问题进行了研究。探讨了样品的化学结构与上述问题间的关系。     

润滑剂对聚氨酯弹性体的反增塑效应

聚氨酯嵌段聚合物的硬链段易于聚集形成微晶相分散于软链段连续相中,原位组成橡塑合金使聚氨酸弹性体兼具高模量、高动态力学性能、高耐磨性等性质,但是决定这些性质的软、硬段形态结构强烈地受组成和制备工艺的影响,使聚合物具有优良的综合性能并不简单．影响软、硬段...     

羧酸型聚乙二醇聚氨酯离聚物及其导电性能

以聚环氧乙烷（ＰＥＯ）为软段，与４，４’－二苯甲烷二异氰酸酯（ＭＤＩ）预聚，以２，２’－二羟甲基丙酸（ＤＭＰＡ）扩链合成了含羧酸基团的聚氨酯，并经中和形成了含不同金属离子的离聚物．测定了样品的热分析数据和力学性能，利用交流阻抗分析仪测定了样品的阻抗谱，由此计算出样品的离子电导率．这类样品由于阴离子（－ＣＯＯ－）固定在聚合物分子链上，因此只有单一阳离子迁移．结果表明，羧酸型聚氨酯离聚物既有较高的单一离子电导率又具有优良的力学性能．讨论了不同软段分子量、硬段含量和金属抗衡离子对离子电导性能的影响     

脂肪族水性聚氨酯的动态力学行为研究

合成了一系列脂肪族水性聚氨酯 .考察了软段的组成、软段分子量及DMPA用量对产物动态力学性能的影响作用 .实验结果表明 ,软段的化学结构对水性聚氨酯的相态结构影响很大 .聚醚型水性聚氨酯具有较低的软段玻璃化转变温度 (Tgs) .聚醚型产物的微相分离程度高于聚酯型产物 .当采用聚酯和聚醚二元醇为混合软段时 ,Tgs随软段中聚醚含量的提高而逐渐降低 .提高DMPA用量 ,软段玻璃化转变温度Tgs移向低温区 ,硬段玻璃化转变温度Tgh移向高温区 ,说明体系的微相分离程度加大 .当软段分子量较低时 ,产物为半相容结构 ,只有一个主转变峰 ,软段的玻璃化转变以肩峰的形式出现 ;当软段分子量较高时 ,产物的微相分离程度较高 ,可以分别观察到软段及硬段的玻璃化转变 .总之 ,通过改变软段的种类、组成和分子量以及DMPA用量 ,可以大幅度地改变水性聚氨酯的形态结构 .     

不同软段聚氨酯的透气性研究

热塑性聚氨酯弹性体是一种包含有软、硕段的多嵌段聚合物,有关其结构与性质的研究已有很多报道^[1,2],但对它的透气性质研究尚少.McBride^[3]和 Knight^[4]等曾对不同硬段含量、不同扩链剂的聚氨酯透气性质作过研究.本工作着重研究不同软段结构和软段长度对聚氨酯透气性的影响,以及含混合软段的聚氨酯的透气性.     

不同软段结构的双离子型聚氨酯离聚体

本文讨论了以聚环氧乙烷(PEO)、聚环氧丙烷(PPO)以及聚丁二烯(PBD)为软段,以4,4’-二异氰酸二苯甲烷(MDI)和N,N-二羟乙基甲胺(MDEA)为硬段的链段型聚氨酯的合成。并通过MDEA中的第三胺与Υ-丙磺内酯反应,转化为双离子型离聚体。用差示扫描量热、红外光谱、动态力学性能以及应力-应变等实验方法研究了化学组成和氨磺化程度对材料相分离程度,力学性能和形态结构的影响。结果表明,离子化后的材料力学性能有很大的改善。对PBD为软段的材料,离子化只能提高硬段“微区”的内聚能,而对PEO、PPO为软段的材料,还能大大提高软、硬相的相分离程度。     

聚氨酯弹性体的相区相容性和阻尼性能研究

合成了一系列含有不同软段的聚氨酯嵌段共聚物及接枝共聚物,并测试了其动态力学性能,结果表明,聚氨酯共聚物的相容性与大分子的链结构有关,接枝链的存在对聚氨酯嵌优共聚物相空性和阻尼性能有很大影响。     

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.     

Polyether-polyester and HMDI Based Polyurethanes:Effect of PLLA Content on Structure and Property

Thermoplastic poly(ether-ester-urethane)s were synthesized from poly(L-lactide) diols (PLLA diols),polytetrahydrofuran diol(PTMG diols),4,4'-dicyclohexylmetlhane diisocyanate (HMDI),and 1,4-butanediol (BDO) by a two-step reaction,and the morphology and property of the resultant TPU could be adjusted by varying the PLLA contents.The soft segment was composed of PLLA and PTMG diols.By controlling the percentage of PLLA in the soft segment,the glass transition temperature and mechanical properties of the polyurethanes could be regulated.Based on the FTIR spectrum,we found that two kinds of hydrogen bonding existed individually in soft matrix and hard domain.The hydrogen bonding in soft matrix was unstable,which could be destroyed during elongation.With in situ stretching WAXS and SAXS experiments,we found that the PLLA crystal was destroyed and the PLLA domain oriented along the stretch direction.Finally,we proposed a schematic model to illustrate the microstructures of these elastomers before and after stretch.     

Morphology and Mechanical Properties of Thermoplastic Polyurethanes Containing Polyisobutylene/Poly(tetramethylene oxide) Mixed Segments

We investigated the thermal properties, microphase separated structure and mechanical properties of a series of thermoplastic polyurethanes (TPUs) containing both polyisobutylene (PIB) and poly(tetramethylene oxide) (PTMO) diols in the soft segment (SS). A series of TPUs were prepared with the same weight fraction of the SS but different ratio between PIB and PTMO diols. Molecular weight of the PTMO diol and chemical structure of the hard segment (HS) also varied. Dynamic mechanical analysis (DMA) measurements did not reveal strong microphase separation between PIB and PTMO in the SS. While it has been assumed that incorporating PTMO diol into the SS can enhance the phase mixing between the hard segment (HS) and SS, our results indicated that, in most cases, the degree of microphase separation of TPUs based on mixed diols is slightly higher than that of TPUs based on only PIB diol.     

Synthesis and properties of poly(ester urethanes) based on cellulose triacetate

Segmented poly(ester urethanes) were synthesized from oligomeric cellulose triacetate diols, poly(caprolactone)diols, and 1,6-hexamethylene diisocyanate. The effects of the molecular mass and structure of soft and hard segments of poly(ester urethanes) on their thermal behavior, mechanical properties, and degradation in aqueous solutions of a phosphate buffer were studied by DSC and IR spectroscopy. The combination of soft segments derived from poly(caprolactone)diols with M = (1.0–3.5) × 10³, hard segments based on depolymerized cellulose triacetate with M = (2–4) × 10³, and 1,6-hexamethylene diisocyanate makes it possible to synthesize poly(ester urethanes) with excellent mechanical characteristics. The degree of crystallinity of these polymers increases with a decrease in the molecular mass of the depolymerized cellulose triacetate block in the hard segment. As the soft segment lengthens, phase separation between domains of soft and hard segments becomes more pronounced. Upon incorporation of poly(ethylene glycol) blocks into the soft segments of poly(ester urethanes), their hydrophobicity is enhanced and biodegradability is accelerated.     

含有偶氮染料侧基的聚氨酯（脲）的研究

用扩链法合成了一系列含有偶氮染料的侧基聚氨酯和聚脲。ＴＦ－ＩＲ、ＤＳＣ、ＤＭＡ的研究表明，聚合物有良好的力学性能，样品中软硬段的含量决定材料的物理性能。通过ＵＶ的测定，计算出样品均有较高的三阶非线性光学（ＮＬＯ）系数。     

Poly(urea)urethanes based on amorphous quaternizable hard segments and a crystalline polyol derived from castor oil

A set of poly(urea)urethanes (PUU), with different contents of amorphous hard segment and castor oil-derived crystalline polyol as soft segment, was prepared combining bulk and solution polymerizations. It is shown that both the soft segment crystallinity and hard segment glassy nature control the stiffness of the materials and that phase mixing at intermediate hard segment compositions produces softer materials. Upon yielding, PUU developed large plasticity associated to the nature of soft segments. At longer strains, PUU presented strain-induced crystallization related both to soft segments alignment and crystallization, leading to strong and tough materials, especially with high hard segment content compositions. Despite the hydrophobicity of the soft segments, the PUU with 65 wt% hard segment content was dispersable in water after quaternization with acetic acid. The high amount of urea groups in this quaternized PUU makes one think of these types of polymers as promising water soluble environmentally friendly strong adhesives, coatings, or water soluble polymeric electrolites.     

A Non-isocyanate Route to Poly(ester urethane) with High Molecular Weight: Synthesis and Effect of Chemical Structures of Polyester-diol

A series of non-isocyanate linear high molecular weight poly(ester urethane)s(PETUs)were prepared through an environmentallyfriendly route based on dimethyl carbonate,1,6-hexanediol and 1,6-hexanediamine.In this route,the polyurethane diol was first prepared by the reaction between bis-1,6-hexamethylencarbamate(BHC)and 1,6-hexanediol.A series of polyester soft segments of polyurethane have been synthesized from the polycondensation of adipic acid and different diols,including butanediol,hexanediol,octanediol and decanediol.The subsequent polycondensation of polyurethane diol and polyester diol led to linear PETUs.The resultant polymers were characterized by GPC,FTIR,¹H-NMR,¹³C-NMR,DSC,WAXD,TGA and tensile test.The results indicated that PETUs possess weight-average molecular weights higher than 1×10⁵ and the tensile strength as high as 10 MPa.The thermal properties,crystallization behavior,microphase separation behavior and morphology were studied by DSC and AFM,and the results indicated that the degree of phase separation was affected by two factors,the crystallization and hydrogen bonding interaction between soft segment and hard segment.     

Thermal Properties and Morphology of Poly(Ester-Urethanes) Prepared from Polycaprolactone-Diol

The soft segment crystallinity and morphology of poly(ester-urethanes) (PEUs) based on poly(ε-caprolactone) (PCL) as a soft segment and an aliphatic diisocyanate in the hard segment were studied. It was found that the restriction of the crystallization of the PCL soft segment depends on the hard segment concentration, the length of the soft segment, and the total molecular mass of the PEUs. The PEU based on a low molecular mass PCL (M=2000) is an amorphous elastic material during a long time after casting from solution or after melt crystallization. A soft-hard segment endothermal mixing transition (T_mix) of about 70-80°C is observed in the DSC curves of this PEU sample. This revised version was published online in August 2006 with corrections to the Cover Date.     

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     

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.     

Characterization of Chain Motion and Phase Structure of Aromatic Waterborne Polyurethane Film Using Intrinsic Fluorescence Spectra

The phase structure and macromolecular chain motion of aromatic waterborne polyurethane film were examined by the fluorescence technique. Excimer emission of the phenyls appears at 436 and 468 nm and is temperature dependent, suggesting that the hard segments in the intermediate phase can be locally oriented. Binding energy of the excimer structure determined by the intrinsic fluorescence spectra is 16 kJ/mol. The intrinsic fluorescence technique can supply more information than the DSC method on segment relaxations, including α-relaxation for the hard or soft segments, β-relaxation of small molecular units, crystallization of the soft segments, γ-relaxation of the classical consecutive –CH₂– units, and even phase separation degree.