咪唑系水性封闭型聚异氰酸酯交联剂的制备与性能

以异佛尔酮二异氰酸酯(IPDI)和2,2-二羟甲基丙酸(DMPA)制备亲水性的异氰酸酯(NCO)封端的线型预聚体,再以预聚体与三羟甲基丙烷(TMP)反应合成支化结构中间体,最后以8种咪唑(IDZ)衍生物分别对残留的NCO基团进行封闭,制得一系列水性封闭型聚异氰酸酯交联剂。以傅里叶变换红外光谱表征了交联剂的结构,以热分析法着重研究了封闭剂的结构对交联剂解封温度的影响,结果表明交联剂的最低解封温度为100℃;稳定性研究表明交联剂在水性聚氨酯乳液中有较好的力学稳定性和适用稳定性。     

环氧改性水性聚氨酯的合成及因素分析

用异佛尔酮二异氰酸酯(IPDI)、聚丙二醇2000(PPG2000)、2,2-双(羟甲基)丙酸(DMPA)为主要原料合成预聚体,环氧树脂(E44)开环合成环氧改性水性聚氨酯(EWPU),考察了不同影响因素对EWPU乳液及胶膜性能的影响。首先,通过FT-IR证实了环氧改性水性聚氨酯的合成;然后,经过TG测试证明了改性后水性聚氨酯耐热性能优于水性聚氨酯;最后详细探究了DMPA量、—NCO与—OH的摩尔比(R值)、硬单体配比以及环氧量对EWPU乳液粒径、贮存稳定性、涂膜耐水性、涂膜耐磨性和力学性能的影响。结果表明,当DMPA量为5%、R值为1.5、硬单体配比为35%、EP量为8%时,EWPU乳液的综合性能最优。     

聚己内酯三醇型水性聚氨酯胶黏剂的合成及性能

以三羟甲基丙烷(TMP)引发ε-己内酯(ε-CL)开环聚合,制得支化结构的聚己内酯三醇(PCL),以此为软段,异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)为主要原料,合成了主链为交联结构的水性聚氨酯胶黏剂(WPU)。讨论了R值(NCO/OH)、DMPA含量,聚己内酯三醇相对分子质量对水性聚氨酯乳液及胶膜性能的影响。结果表明,当R值为2.5、二羟甲基丙酸的质量分数为4%~5%、聚己内酯三醇的相对分子质量为1500、中和度为100%时,制得的乳液贮存稳定,粒径较小,胶膜的成膜手感较好,并具有较好的耐水性及力学性能。胶膜在270℃以下具有较好的热稳定性。     

双重交联PUEA复合乳液的合成

以甲苯二异氰酸酯(TDI-80)、聚醚二元醇(GE-210)、二羟甲基丙酸(DMPA)、甲基丙烯酸甲酯(MMA)等为主要原料,以环氧树脂(CYD-014)为预交联剂,以甲基丙烯酸缩水甘油酯(GMA)为后交联剂,采用预聚体法,合成了具有双重交联结构的PUEA复合乳液。研究了后交联剂GMA用量对乳液和涂膜性能的影响及交联固化工艺条件。结果表明,GMA的用量对PUEA乳液及涂膜性能有重要影响。当GMA用量为3%时,乳液外观和稳定性好,烘烤成膜的涂膜吸水率和吸乙醇率最低,硬度和耐冲击性能优异,防腐性能最佳;加入GMA的后交联PUEA涂膜性能与成膜温度及烘烤时间有密切关系;适宜的成膜条件为150℃/20min。     

内交联水性聚氨酯涂膜性能的影响因素

以异氟尔酮二异氰酸酯、1,6-己二异氰酸酯、二羟甲基丙酸、聚氧化丙烯二醇和聚己二酸-1,4丁二醇酯为原料,合成了一系列内交联水性聚氨酯分散体(WPU)。研究了NCO/OH物质的量比和内交联剂三羟甲基丙烷(TMP)用量对水性聚氨酯涂膜性能的影响,并通过红外光谱(FT-IR)、接触角测量、热重分析(TGA)和X射线衍射(XRD)等对涂膜性能进行了表征。实验结果表明,NCO/OH物质的量比和TMP含量的增加均会使涂膜拉伸强度增加。XRD分析表明,软段微区的结晶性能随着二羟甲基丙酸(DMPA)含量的增加而减小,当DMPA的质量分数增加至5.6%时,软段微区表现出非晶态。     

1,5-萘二异氰酸酯的反应活性及预聚体制备EI北大核心CSCD

基于1,5-萘二异氰酸酯(NDI)的聚氨酯预聚物仅具有限的存储稳定性,为研究其原因,采用动力学实验和量化计算研究了NDI的反应活性。从结果看,NDI的活性不高于常见芳香族异氰酸酯4,4’-二苯基甲烷二异氰酸酯(MDI)和2,4-甲苯二异氰酸酯(TDI),甚至低于脂肪族的1,6-六亚甲基二异氰酸酯(HDI)。结合实验数据和文献分析,发现在NDI型预聚体合成中较高反应温度(120~130℃)会导致异氰酸酯与氨基甲酸酯的支化副反应,导致预聚体存放或浇注时凝胶失效。通过在合成过程中加入抑制剂磷酸的方法可以获得稳定耐储存NDI型聚氨酯预聚体,并且随着磷酸含量的增加,预聚体的相对分子质量和黏度以及后固化得到的聚氨酯弹性体的力学性能均有所下降。     

高固含量无溶剂水性聚氨酯的结构和性能

以异佛尔酮二异氰酸酯(IPDI)、聚己二酸丁二醇酯二醇(PBA)、二羟甲基丁酸(DMBA)、丁二醇(BDO)等为主要原料,在不添加任何油性溶剂的情况下,合成了高固含量的无溶剂水性聚氨酯,并对该无溶剂水性聚氨酯乳液和胶膜的结构和性能进行了研究。结果表明:该无溶剂水性聚氨酯为聚酯型;其乳液黏度随固含量的增加而增大;其胶膜的结晶性能随着软段分子量的增加而增强,随着R值(异氰酸酯基与羟基的比值)的增加而降低;胶膜的拉伸性能则随着固含量的增加而有所降低。     

阳离子水性聚氨酯乳液的合成及性能

以二异氰酸酯和聚酯二元醇合成聚氨酯预聚体,采用N-甲基二乙醇胺(N-MDEA)为亲水扩链剂,制备了阳离子水性聚氨酯(CWPU)乳液,研究了制备CWPU乳液的影响因素,并研究了CWPU乳液涂膜的拉伸性能。研究表明,当N-MDEA的质量分数为7.0%-9.5%,R值为1.3-1.5,中和度为80%-100%时,可制得稳定性较好的CWPU乳液。随着N-MDEA含量增加,CWPU乳液涂膜拉伸强度增加,断裂伸长率下降;随着中和度的提高,涂膜拉伸强度和断裂伸长率同时提高。     

聚氨酯胶粘剂的制备、性能及其交联改性研究

以聚醚多元醇（GE210）、1，4一丁二醇和甲苯-2，4-二异氰酸酯（TDI）等为原料，以聚酯多元醇（P210）为交联剂，合成了具有不同异氰酸酯指数（R值）的线型和交联型两类溶剂型聚氨酯胶粘剂。通过红外谱图（FT-IR）表征了聚氨酯的结构，测定了所合成的聚氨酯胶粘剂的物理性能及其对皮革基材的粘接性能。结果表明，线型聚氨酯胶粘剂对皮革具有较强的粘接强度，且随着异氰酸酯指数的增加，粘接强度逐渐增强。加入交联剂后，随R值增大，胶粘剂的粘接强度也逐渐增大。在相同R值的情况下，交联型聚氨酯胶粘剂比线型聚氨酯胶粘剂的粘接强度有较大程度的提高。     

聚碳酸酯型聚氨酯薄膜的制备及性能研究

目的 采用六亚甲基二异氰酸酯（HDI）、聚碳酸酯二元醇（PCDL）和己二醇（HDO）合成一种新型聚氨酯,研究R值（在整个预聚反应中异氰酸酯与羟基的摩尔比）对聚氨酯薄膜（PU膜）性能的影响。方法 采用预聚法将不同R值的原料进行化学合成,然后流延成膜。分析R值对PU膜力学性能、水接触角、透明度和氧气透过性的影响,并通过红外光谱、差示量热扫描分析和热重分析对PU膜进行测试表征。结果 随着R值的增加,PU膜的力学性能和热稳定性变好,水接触角和微相分离程度增大,透明度和氧气透过系数降低。结论 使用以上3种原料合成了一种新型聚氨酯,且随着R值的增加,PU膜的综合性能得到提升。     

Synthesis and characterization of castor oil based polyurethane-polyacrylonitrile interpenetrating polymer networks

A series of interpenetrating polymer networks (IPNs) of castor oil based polyurethane/polyacrylonitrile (PU/PAN: 80/20, 60/40, 50/50, 40/60 and 20/80) were synthesized by condensation reaction of castor oil with methylene diisocyanate and acrylonitrile, employing benzoyl peroxide (BPO) and ethylene glycol dimethylacrylate (EGDM) as initiator and crosslinkers respectively. The physical, chemical, optical and some of the mechanical properties of PU/PAN were studied. Phase stabilization in IPNs was investigated by wide angle X-ray (WAXS) profile analysis. Variation of crystal size distribution was studied in these polymer networks. Paper presented at the 5th IUMRS ICA98, October 1998, Bangalore     

聚酯型聚氨酯薄膜的制备及性能研究

目的 以1,6-六亚甲基二异氰酸酯（HDI）、聚已二酸-1,4-丁二醇酯（PBA）、二甘醇（DEG）为原料制备聚酯型聚氨酯（PU）薄膜,并研究异氰酸根与氢氧根的比值（R值）对薄膜性能的影响。方法 采用预聚物法制备PU,反应所需要原材料的质量通过不同R值来确定。将制得的PU产物加入DMF进行溶解,然后使用流延方法获得薄膜,随后使用红外光谱进行表征;对薄膜的力学性能、透氧性能、热力学性能、透光性以及亲疏水性进行检测。结果 这种薄膜具有良好的力学性能。随R值的增大,断裂伸长率呈下降趋势,拉伸强度先增大后降低;透光性和阻隔性随R值增大而降低;疏水性随R值增大而增大。结论 证明了用HDI和PBA合成PU的可行性,且R值的变化对PU薄膜性能有很大影响。     

高度支化水性聚氨酯的合成及性能

以甲苯-2,4-二异氰酸酯(TDI)、聚碳酸酯二醇(PCDL)、二羟甲基丙酸(DMPA)和聚醚胺(ATA)为原料,采用A2+B3法合成了具有高度支化结构的水性聚氨酯(HBAPU)乳液。用红外光谱(FT-IR)对产物结构进行表征;用光子相关光谱(PCS)研究了乳液的稳定性能,NCO/OH=1.3,w(DMPA)=6%时可以得到稳定的HBAPU乳液;采用旋转黏度计、差式扫描量热仪(DSC)、热失重分析仪(TG)、电子拉力机对产物的流变行为和各种性能进行了测试。结果表明,相对于线性水性聚氨酯(LAPU),HBAPU产物具有较低的黏度、良好的热稳定性、较高的Tg和拉伸强度。     

Structure-property relationship of castor oil based diol chain extended polyurethanes (PUs)

A series of 1,4-butane diol and 1,6-hexane diol based chain extended polyurethanes (PUs) have been prepared using castor oil with different diisocyanates such as methylene bis (phenyl isocyanate) (MDI), toluene-2,4-diisocyanate (TDI) and hexa methylene diisocyanate (HMDI) as crosslinkers. The prepared aliphatic diol based chain extended PU's have been characterised for physico-mechanical properties such as density, tensile strength, percentage elongation at break, tensile modulus and surface hardness; and optical properties like total transmittance and haze. The properties imparted by the chain extenders and diisocyanates on PUs have been explained on the basis of chemical structure. Effect of heat aging on mechanical properties of PUs have also studied. These changes have been interpreted quantitatively in terms of microcrystalline parameters computed using wide-angle X-ray scattering (WAXS) data.     

Soft-type polyurethane foams derived from molasses

Molasses (ML)-based soft-type polyurethane (PU) foams were successfully prepared by controlling evolved heat during chemical reaction. Two kinds of isocyanate, poly(phenylene methylene) polyisocyanate (MDI) and tolylene diisocyanate (TDI), and polypropylene glycol with a long molecular chain length were utilized to control the chemical reaction. The hydroxyl group in ML was used as the reaction site and soft-type PU foams were synthesized at isocyanate (NCO)/hydroxyl group (OH) ratios of 1.05. Mechanical properties of the above foams were controlled by changing the mixing ratio of MDI and TDI. Pore size and distribution were measured by scanning electron microscopy. With increasing thickness of cell wall, compression strength and modulus increased. Thermal properties of PU foams were investigated by differential scanning calorimetry, thermogravimetry, and thermal conductivity measurements. Two-step glass transition temperatures were observed at around ca. ?55 and 80 °C, regardless of kind of isocyanate. The low temperature side glass transition is attributed to the molecular motion of long oxyethylene chains and the high temperature side transition is caused by rigid components including saccharide components. Thermal decomposition of PU foams started from ca. 270 °C. Thermal conductivity of soft-type PU was observed in a range from 0.034 to 0.035 J s^?1 m^?1 K^?1.     

超支化聚酰胺酯的合成及在聚氨酯中的应用

以丁二酸酐和二异丙醇胺为原料制备了AB2型单体,用三羟甲基丙烷作为核分子通过与AB2型单体进行反应,合成了不同代数的超支化聚酰胺酯(HBP)。采用红外光谱(IR),凝胶渗透色谱(GPC),羟值和黏度测定对其进行了表征,结果表明,合成的HBP具有较为规整的分子结构和较窄的分子量分布。将HBP作为交联剂用于聚氨酯固化体系,并对其力学性能进行了分析,发现当第三代HBP作为交联剂时,固化体系显示出最佳的拉伸性能和撕裂强度,当第四代HBP作为交联剂时,体系具有最高的硬度及Tg。     

Synthesis and characterization of photoactive polyurethane elastomers with 2,3-dihydroxypyridine in the main chain

Photoactive polyurethane elastomers with pyridine derivatives in the polymer backbone were synthesized by chain-extending isocyanate end-capped prepolymers with 2,3-dihydroxypyridine. The isocyanate-terminated prepolymers were obtained from poly(tetramethylene oxide) glycol of molecular weight 1400 (Terathane 1400) and 1,6-hexamethylene diisocyanate. The properties of the linear heterocyclic polyurethane were compared with properties of the crosslinked heterocyclic polyurethane obtained by chain extension with various crosslinkers. Heterocyclic polyurethane elastomers were characterized using Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), dynamic mechanical analysis (DMA), contact angle measurements, and mechanical analysis. Static mechanical measurements showed greater elongation and tensile strength for polyurethanes with a lower content of heterocyclic groups in the hard segment. The static contact angles of the cast films of these polymers indicated that the nature of the hard segment influences the surface polarity. The dynamic mechanical spectra revealed that linear polymers have two transition temperatures as results from a clear phase separation caused by high-intermolecular hydrogen bonds in the regions of pyridine units and urethane groups. Polyurethane elastomer films with pyridine moieties in the main chain form a photosensitive material. If stored in laboratory conditions (light, ambient air atmosphere), the color of the films changes from white to black. These photo-induced structural changes are studied by H NMR measurements.     

封闭型异氰酸酯交联剂的制备及其固化行为的研究

合成了５种封闭型的异氰酸酯交联剂。用动态扭辩分析（ＴＢＡ）测定交联剂与聚丙烯酸酯固化的宏观性能,固化分为两阶段,用ｉｎ Ｓｉｔｕ ＦＴ－ＩＲ研究了固化瓜的分子机构,得出第一阶段是封闭的小分子脱去后,异氰酸根向聚丙烯酸酯上的羟基转移的固化反应;第二阶段是解封后的氰酸根向氨基甲酸片段上的氢转移的深度固化反应。用计算机模拟得到交联剂分子的最低能量构象图,提出了封闭型ＴＤＩ交联剂由于空间位阻效应而发生了三     

Effect of the hard segment chemistry and structure on the thermal and mechanical properties of novel biomedical segmented poly(esterurethanes)

Two series of biomedical segmented polyurethanes (SPU) based on poly(ε-caprolactone) diol (PCL diol), 1,6-hexamethylene diisocyanate (HDI) or l-lysine methyl ester diisocyanate (LDI) and three novel chain extenders, were synthesized and characterized. Chain extenders containing urea groups or an aromatic amino-acid derivative were incorporated in the SPU formulation to strengthen the hard segment interactions through either bidentate hydrogen bonding or π-stacking interactions, respectively. By varying the composition of the hard segment (diisocyanate and chain extender), its structure was varied to investigate the structure-property relationships. The different chemical composition and symmetry of hard segment modulated the phase separation of soft and hard domains, as demonstrated by the thermal behavior. Hard segment association was more enhanced by using a combination of symmetric diisocyanate and urea-diol chain extenders. The hard segment cohesion had an important effect on the observed mechanical behavior. Polyurethanes synthesized using HDI (Series H) were stronger than those obtained using LDI (Series L). The latter SPU exhibited no tendency to undergo cold-drawing and the lowest ultimate properties. Incorporation of the aromatic chain extender produced opposite effects, resulting in polyurethanes with the highest elongation and tearing energy (Series H) and the lowest strain at break (Series L). Since the synthesized biodegradable SPU possess a range of thermal and mechanical properties, these materials may hold potential for use in soft tissue engineering scaffold applications.