不同分子量软链段的聚已内酯型聚氨酯扩链反应动力学研究

合成了一系列不同分子量的聚已内酯，进而制备异氰酸根封端的聚已内酯预聚体，用傅里叶变换红外光谱研究了不同分子量的聚已内酯预聚体与二元醇的扩链反应。扩链反应动力学研究结果表明：聚已内酯预聚体与二元醇的扩链反应均为二级反应；随着软链段反应物料分子量的增加，反应速率常数显著降低，但当分子量超过某一范围后，其对反应速率的影响逐渐减小，趋于不变。对于不同硬链段反应物料含量扩链反应体系，硬链段反应物料含量越高，软链段反应物料分子量对反应速率的影响越明显，而且，当软链段反应物料分子量超过某一范围后，不同体系的反应速率常数间的差值趋于不变。Arrhenius方程中的指前因子（B）随软链段反应物料分子量的变化关系与速率常数对分子量的依赖关系相同；从反应速率常数对温度的依赖关系可见：表观活化能的直线斜率基本相同，扩链反应的活化能主要一官能团的反应活性相关。     

PCL-PEG-PCL嵌段共聚物的合成与性能

研究了氮气保护下，以辛酸亚锡和聚乙二醇为共引发剂，引发ε－己内酯的开环聚合反应。在聚乙二醇（PEG）链段分子量保持不变的情况下，全盛了不同分子量聚己丙酯链段的PCL－PEG－PCL三嵌段共聚物，以及不同分子量PEG链段而聚己内酯链段相同的嵌段共聚物。采用GPC、DSC、FTIR、^1H-NMR及吸水性测试等分析手段表征了共聚物的结构和性能。结果表明聚合反应为可控反应，可通过调整聚乙二醇与ε－己内酯的比例来控制聚合物的分子量；聚乙二醇组分的引入有效地改善了聚合物的亲水性，并破坏了其结晶性。     

MDI与TDI封端聚酯预聚物和扩链剂间反应速率的研究

用ＦＴＩＲ法系统地研究了不同硬段结构对聚酯型聚氨酯扩链反应动力学的影响，结果显示：不同类二异氰酸酯ＭＤＩ和ＴＤＩ形成的ＮＣＯ封端的聚酯预聚体与二元胺（ＭＯＣＡ）和三元醇（ＴＭＰ）的扩链反应均为二级反应，由ＭＤＩ形成ＮＣＯ封端的聚酯预聚体与胺或醇的扩链反应速度比ＴＤＩ类的要快，ＭＯＣＡ扩链比ＴＭＰ扩链反应活化能低，从基团反应活性不同体系扩链反速度的差别进行了讨论。     

聚酰胺-聚ε-己内酯多嵌段共聚物合成、表征及反应动力学的研究

本文采用双羧基尼龙1010预聚物和双羟基聚δ-己内酯预聚物经熔融缩聚制得了不同嵌段链长度和不同软硬链段含量的尼龙1010-聚δ-己内酯多嵌段共聚物,并通过分子量(VPO)、核磁共振谱(~1H NMR)和热分析法(DSC)对该共聚物进行表征。同时,对尼龙1010和聚δ-已内酯熔融缩聚反应动力学作了研究。结果表明,该反应为二级反应,活化能为ΔΕ=58.2kcal/mol,反应常数K=1.36×10~(22)·e~(-2.93×10~4/T)。     

聚酰胺-聚ε-己内酯多嵌段共聚物合成、表征及反应动力学的研究

本文采用双羧基尼龙1010预聚物和双羟基聚δ-己内酯预聚物经熔融缩聚制得了不同嵌段链长度和不同软硬链段含量的尼龙1010-聚δ-己内酯多嵌段共聚物,并通过分子量(VPO)、核磁共振谱(¹HNMR)和热分析法(DSC)对该共聚物进行表征。同时,对尼龙1010和聚δ-已内酯熔融缩聚反应动力学作了研究。结果表明,该反应为二级反应,活化能为ΔΕ=58.2kcal/mol,反应常数K=1.36×10²²·e^-2.93×104/T。     

反应挤出合成带不饱和官能团端基的聚己内酯

用带双键官能团的2-烯丙氧基乙醇与四丙醇钛酸酯进行酯交换,可合成用于ε-己内酯配位开环聚合的钛化合物引发剂;利用此引发剂,引发ε-己内酯聚合得到了分子链一端为双键的功能化聚己内酯.研究了物料配比和反应温度对聚合转化率和速率的影响,进而在双螺杆挤出机中实施快速本体聚合,合成了带活性双键的功能化聚己内酯.引发剂和聚合物的化学结构由 1H-NMR予以表征,GPC测定的结果表明聚合物的分子量与物料摩尔比相关.     

聚酯-聚酯多嵌段共聚物序列结构研究

利用对苯二甲酸乙二酯-己内酯多嵌段共聚物质子谱中各官能团的特征共振吸收峰计算证明两种吸收强度关系式反映了软链段和硬链段中相应官能团的数量关系,从而进一步肯定了所提出的链化学结构,在此基础上又直接利用各种官能团对其质子谱中特征吸收峰的强度贡献,计算得到多嵌段共聚物中软硬链段数,软硬链段平均长度,分子量和硬链段重量百分数的表示式。本文最后一部分用三素组的几率计算方法对多嵌段共聚物的质子谱和~(13)C谱分析讨论,所得有关链结构的数量关系是合理的,进一步证实了质子谱的直接计算法。     

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。     

主链含四重氢键基元聚氨酯的合成与性能

合成了一种新型含有UPy(2-ureido-4[1H]-pyrimidone)基团的二羟基化合物,以此二羟基化合物作扩链剂,通过与聚氨酯预聚体进行的扩链反应,制备了一系列主链含UPy的聚氨酯(PU-UPy).傅里叶红外光谱(FTIR)、氢核磁共振(1H-NMR)等测试结果表明,在聚氨酯主链中确实含有UPy链段.同时,热性能及力学性能测试表明,聚氨酯中的UPy二聚体会集聚而形成微晶,熔点在60℃附近.在聚氨酯主链中引入UPy,能大幅提高聚氨酯的力学性能,调整软段的分子量,以及在主链中UPy含量可改变聚氨酯弹性体的断裂伸长率和抗张强度.     

含聚醚间隔链的扩链脲改性环氧树脂/双氰双胺固化体系性能研究

合成了一系列含不同分子量聚环氧丙烷 (PPG)柔性间隔链的扩链脲 ,系统考察了扩链脲改性环氧树脂E 5 1/双氰双胺 (dicy)固化体系的固化反应活性、动态力学行为、冲击性能和断裂面形态结构 ,并对体系的冲击性能、形态结构与动态力学行为之间的关系进行了探讨 .结果表明 ,改性体系固化反应活性明显提高 ,固化反应表观活化能降低 ,固化反应峰顶温度从 190℃降低至 14 0℃ ,固化反应的表观活化能由 14 5 5kJ/mol降至 70～ 80kJ mol;改性体系冲击强度明显提高 ,其中所含PPG柔性链分子量为 10 0 0的扩链脲改性的E 5 1/dicy体系冲击强度较未改性的E 5 1/dicy体系提高了 8倍 ,其冲击试样断裂面的形态具有明显的韧性断裂特征 ,微观两相网络结构的存在导致了改性体系冲击强度显著提高     

相同软硬段质量配比聚醚酯弹性体PEG/PBT的结构与表征

以熔融缩聚法合成了一系列聚乙二醇(PEG)/聚对苯二甲酸丁二醇酯(PBT)聚醚酯热塑性弹性体,用NMR,FTIR,DSC及力学性能测试等方法表征了材料的结构及性能.讨论了在相同软硬段质量配比下,不同软硬段长度对材料性能的影响.结果表明,随着软段PEG长度增加,硬段PBT长度相应增长,弹性模量基本保持不变,抗拉强度、屈服应力及特性粘度增加.     

Synthesis of Polycarbonate Diols(PCDLs) via Two-step Process Using CH3COONa as an Effective Catalyst

Polycarbonate diols(PCDLs) with a number average molecular weight(M_n) of 2800 and a narrow polydispersity index(PDI=1.33) were synthesized from dimethyl carbonate(DMC) and 1,4-butanediol(BD) via a two-step process. The influences of the molar ratios of DMC to BD in the feedstock, polycondensation temperature and polycondensation time on the PCDLs preparation were studied. CH₃COONa showed the best catalytic performance among the catalysts studied. The highest BD conversion of 73.8% and PCDLs yield of 64.7% were achieved under its optimum reaction conditions. Furthermore, based on the results of ¹H NMR, the relationships between the ratio of end groups (-OCH₃/-OH) of oligomers, the M_n and chain-end constitute of resultant polycarbonates were also investigated. The results indicate that PCDLs can be synthesized when the oligomers mostly bear hydroxyl end groups. In contrast, it was impossible to prepare PCDLs when the oligomers were enriched with methyl carbonate end groups.     

短链药物聚电解质稀溶液行为

本文用改良型Bruss膜渗透计及动态渗透压、粘度和电导法研究了一种主链含5-氟尿嘧啶的磷酸酯缩聚物盐PPA和PPB(24000较小,溶液显示正常渗透压行为,由此得到数均分子量及第二维利系数A₂。它们在水和甲醇中的A₀变大,溶液显示一般聚电解质的性质,但是当溶液浓度相当低时,η_SP/C～C和A～C曲线均出现反常变化。     

Studies on molecular weight distribution of carbon fiber polymer precursors synthesized using mixed solvents

The molecular weight distributions were estimated for carbon fiber polymer precursors such as poly（acrylonitrile-co -itaconic acid） synthesized by semi batch solution polymerization in mixed solvents media with the azonitrile compounds as initiator under the different ratios of solvent and non solvent from 0.75 to 2.5 in weight.The copolymer was characterized by using Fourier transform infrared spectroscopy（FTIR） and nuclear magnetic resonance（¹H-NMR） analyses.The molecular weight distributions were evaluated by M_v/M_n ratios estimated from viscosity and osmotic measurements,and M_w/M_n estimated from size exclusion chromatography.The molecular weight distributions of these polymers as determined from M_v/M_n and M_w/M_n are 2.9 to 3.2 and 2.0 to 2.5 respectively.The molecular distributions were close to a narrow distribution of 2.0 when the solvent/non-solvent ratio was varied between 1.4 and 2.0.Intrinsic viscosity[?]as a function of molecular weight of poly（acrylonitrile-co-itaconic acid） was evaluated by means of low angle laser light scattering with size exclusion chromatography（SEC-LALLS） and viscometry with SEC（SEC-VISCO）.The relationship between[?]and M_w for poly（acrylonitrile-co-itaconic acid） in DMF at 50℃was[?]= 1.1×10^-5M_w^0.79,where[?]is obtained in dL/g.     

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.     

Structure and properties of segmented poly(urethaneurea)s with relatively short hard‐segment chains

We report the structure and properties of segmented poly(urethaneurea) (SPUU) with relatively short hard‐segment chains. The SPUU samples comprised poly(tetramethylene glycol) prepolymer as a soft segment and 4,4′‐diphenylmethane diisocyanate (MDI) units as a hard segment that were extended with ethylenediamine. To discuss quantitatively the conformation of the soft‐segment chain in the microphase‐separated domain space, we used SPUU samples for which the molecular weights of the hard‐ and soft‐segment chains are well characterized. The effects of the cohesive force in the hard‐segment chains on the structure and properties of SPUU were also studied with samples of different chain lengths of the hard segment, although the window of x_H, the average number of MDI units in a hard‐segment chain, was narrow (2.38 ≤ x_H ≤ 2.77). There were urethane groups in the soft segments and urea groups in the hard segments. Because of a strong cohesive force between the urea groups, we could control the overall cohesive force in the hard‐segment chains by controlling the chain lengths of the hard segment. First of all, microphase separation was found to be better developed in the samples with longer hard‐segment chains because of an increase of the cohesive force. It was also found that the interfacial thickness became thinner. The long spacing for the one‐dimensionally repeating hard‐ and soft‐segment domains could be well correlated with the molecular characteristics when the assumption of Gaussian conformation was employed for the soft‐segment chains. This is unusual for strongly segregated block copolymers and might be characteristic of multiblock copolymers containing rod–coil chains. The tensile moduli and thermal stability temperature, T_H, increased with an increase of the cohesive force, whereas the glass‐transition temperature, the melting temperature, and the degree of crystallinity of the soft‐segment chains decreased. The increase in T_H especially was appreciable, although the variation in the chain length of the hard segment was not profound. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1716–1728, 2000     

Aliphatic Segmented Poly(ether ester amide)s Synthesized from Hexanediamine,Sebacic Acid and Poly(ethylene glycol)s

High molecular weight aliphatic segmented poly(ether ester amide)s(PEEAs) were synthesized via melt polycondensation and chain extension. An oligomeric polyamide(PA) terminated mainly with -COOH groups(HOOC-PA-COOH) was prepared from the reaction of nylon 610 salt with sebacic acid. Melt polycondensation of HOOC-PA-COOH with polyethylene glycol(PEG), such as PEG400, PEG600, PEG1000 and PEG1500, was conducted at 200℃, and several segmented PEEA prepolymers(PrePEEAs) were prepared. Chain extension of PrePEEAs was carried out at 190℃ using 2,2'-(1,4-phenylene)-bis(2-oxazoline) and adipoyl biscaprolactamate as combination chain extenders. Chain extended PEEAs(ExtPEEAs) were characterized by gel permeation chromatography(GPC), Fourier transform infrared spectrophotometer(FTIR), proton nuclear magnetic resonance(¹H NMR), differential scanning calorimetry(DSC), wide angle X-ray scattering(WAXS), thermogravimetry analysis(TGA), and tensile test. The ExtPEEAs exhibited M_n up to 98700, T_m from 164.2℃ to 176.1℃, initial decomposition temperature above 320.6℃, tensile strength up to 34.80 MPa, and strain at break from 111.92% to 353.12%. Aliphatic segmented PEEAs with good thermal and mechanical properties were prepared.     

香菇多糖的成分及其分子量研究

从香菇子实体中用0.9%NaCl水溶液、85%乙醇、热水、1%草酸铵、5%NaOH/0.05%NaBH₄和2%NaOH/2%尿素分别提取出四种杂多糖(L-FⅠ-L-FⅣn)和两种葡聚糖(L-FⅤ和L-FⅥn).红外光谱和高效液相色谱分析结果表明杂多糖主要由葡萄糖、葡萄糖醛酸、木糖、甘露糖、半乳糖和鼠李糖组成,而且按照分离过程的进行多糖中葡萄糖含量递增.由光散射和膜渗透压法研究了多糖的重均分子量Mw、均方根旋转半径2>^1/2、第二维利系数A₂及数均分子量M_n.L-FⅡ、L-FⅢ、L-FⅤ及L-FⅥn的M_w值依次为19.7×10⁴、192.3×10⁴、136.4×10⁴和136.7×10⁴,它们的多分散系数-Mw/-Mn在3～5范围.     

水性聚氨酯硬段含量对其氢键相互作用及性能的影响

异佛尔酮二异氰酸酯（IPDI）、二羟甲基丙酸(DMPA)作为硬段,合成了水性聚氨酯。 研究了硬段含量（质量分数）对乳液稳定性、膜耐热和力学性能等的影响。 当硬段质量分数低于26%时,乳液贮存稳定性较差。 随着硬段含量增加,聚氨酯膜拉伸强度迅速增加,断裂伸长率略有降低;红外光谱显示,自由的N-H伸缩振动峰强度减弱,氢键化N-H的振动峰强度增加;同时C=O伸缩振动峰整体向低波数方向移动,C=O伸缩振动峰峰形有明显的变化;DSC测试在50～125 ℃出现明显的氢键解离现象,吸热峰增强,证实了氢键作用力随着硬段含量的增加逐渐增强。 TG测试表明,水性聚氨酯硬段和软段分步解离,随着硬段含量的增加,硬段分解温度降低,水性聚氨酯耐热性能下降。