硬段含量对水性聚氨酯氢键化程度的影响

以聚四氢呋喃醚二醇(PTMG-2000)、异佛尔酮二异氰酸酯(IPDI)、乙二醇(EG)、二羟甲基丙酸(DMPA)和乙二胺(EDA)为原料合成了不同硬段含量的水性聚氨酯(WPU).对FT-IR图谱中氨基与羰基区进行分峰处理,研究硬段含量对氢键化程度的定量影响,利用X射线衍射(XRD)、差示扫描量热(DSC)研究了硬段含...     

硬段含量对聚氨酯脲弹性体力学性能的影响

以二苯基甲烷二异氰酸酯(MDI)与4,4′-双(仲丁基氨基)-二苯基甲烷为硬段、以聚氧化丙烯多元醇(PPG)为软段,采用半预聚法制备了一系列不同硬段含量的聚氨酯脲弹性体。通过静态力学性能测试、动态力学分析等研究手段,考察了硬段含量对聚氨酯脲弹性体力学性能及动态力学性能的影响。结果表明：40%～50%硬段含量弹性体的玻璃化转变温度(T_g)在室温附近(15～30℃),且具有较高的阻尼因子峰值(tanδ_max)、较宽的阻尼温域;随着硬段含量的升高,弹性体的拉伸强度、断裂伸长率逐渐升高,tanδ_max降低,T_g向高温方向移动。     

硬段含量和类型对水性聚氨酯性能的影响

通过实验研究了硬段含量对水性聚氨酯性能的影响,并由此延伸了不同种类的硬段类型对水性聚氨酯的影响,最终获得了良好的结果,对水性聚氨酯的科学利用有很强大的指导作用。     

硬段含量对水性聚氨酯性能的影响

以聚酯多元醇、二羟甲基丙酸(DMPA)、甲苯二异氰酸酯(TDI)和1,4-丁二醇(BDO)为主要原料,合成了阴离子型WPU(水性聚氨酯),并着重探讨了聚氨酯(PU)分子链中硬段含量对其性能的影响。结果表明:随着PU分子链中硬段含量的不断增加,硬段的Tg(玻璃化转变温度)上升,但软段的Tg呈先升后降态势,WPU的外观由半透明泛蓝光转变为乳白色不透明(稳定性变差),并且WPU的黏度、耐水性和T型剥离强度均呈先升后降态势;当WPU中w(硬段)=22.79%时,相应WPU的综合性能相对最好,用其胶接聚酰胺(PA)/聚丙烯(PP)复合薄膜的T型剥离强度达到0.488 kN/m。     

硬段含量对MDI型热塑性聚氨酯性能的影响

以4,4'-二苯基甲烷二异氰酸酯(MDI)、聚四亚甲基醚二醇(PTMG)和1,3-丙二醇(PDO)为原料,采用预聚体法合成热塑性聚氨酯(TPU),利用FTIR、DSC及力学性能测试等手段探究了硬段含量对TP U性能的影响.结果表明,硬段含量增加,TP U的氢键化程度、玻璃化转变温度、硬段熔融温度、拉伸强度、撕裂强度、硬...     

硬段含量对水性聚氨酯性能的影响

以聚酯多元醇和异佛尔酮二异氰酸酯(IPDI)为主要原料，引入亲水单体二羟甲基丙酸(DMPA)，按不同配比合成了系列聚氨酯乳液。考察了硬段含量对乳液粒径、表观黏度、膜吸水性、硬度、力学性能的影响，并通过动态力学性能测试(DMA)研究了软段和硬段的玻璃化转变温度。结果表明：提高-NCP/-0H物质的量之比、DMPA用量均使聚氨酯中软段的玻璃化温度Tg(s)降低，硬段的玻璃化温度Tg(h)升高，△T值增加，软硬段相分离程度增加。随乙二胺用量的增加，会使软段玻璃化转变温度Tg(s)移向高温，软硬段相分离程度降低；硬段含量提高，胶膜硬度增加，拉伸强度增加，胶膜耐水性降低。     

混合聚醚配比对聚氨酯脲结构和性能的影响研究

以PPG600和PPG2000混合聚醚、异佛尔酮二异氰酸酯（IPDI）和异佛尔酮二胺（IPDA）为原料合成溶剂型聚氨酯脲（Puu）树脂,通过改变PPG600和PPG2000配比调节树脂硬段含量。利用FTIR．DSC．TG等研究PPG600和PPG2000配比对聚氨酯脲微观结构、耐热性及力学性能的影响。结果表明,随着混合聚醚中PPG600含量增加,聚氨酯脲软段的玻璃化转变温度（Tg）升高,软硬段的相容性增强,脲羰基氢键化程度降低,树脂的定伸强度增大。     

红外光谱法研究聚氨酯脲氢键

采用间苯二胺为扩链剂制备聚氨酯脲,研究其力学性能。随着硬段含量的增加,产物的硬度和强度均增加,而断裂伸长率下降。并用红外光谱法对氢键化程度进行表征,结果表明：随着硬段含量的增加,其脲羰基区氢键化程度增加。     

硬段含量对非离子型水性聚氨酯氢键化作用的影响

以聚己二酸新戊二醇酯((M)n=2 000)、异佛尔酮二异氰酸酯、1,4-丁二醇和三羟甲基丙烷聚乙二醇单甲醚((M)n=1 000)为原料,合成了一系列梳状非离子型水性聚氨酯(NWPU).通过傅里叶变换红外光谱表征了NWPU的结构并探究了非离子型水性聚氨酯的氢键化作用,通过差示扫描量热仪研究了硬段含量对NWPU胶膜热性...     

聚氨酯硬段含量变化对酪素/聚氨酯乳液及胶膜性能的影响

以异佛尔酮二异氰酸酯(IPDI)、聚四氢呋喃醚二醇(PTMEG1000)、二羟甲基丙酸(DMPA)、一缩二乙二醇(DEG)等为主要原料,固定酪素与聚氨酯的比例,通过改变聚氨酯硬段含量,制备出系列酪素/聚氨酯乳液(CWPU)。讨论了聚氨酯硬段含量的变化对CWPU状态、胶膜力学性能和热机械性能的影响。结果表明,随着聚氨酯硬段含量增加,聚氨酯分子之间、聚氨酯与酪素分子之间的氢键作用力增大,CWPU的粒径增大,分布变宽,乳液的粒径主要分布在100 nm左右;拉伸性能先增大后减小,硬段含量为64.61%时的拉伸强度达到41.75 MPa,断裂伸长率为344.75%。     

热塑性聚氨酯/凹凸棒土复合体系的氢键作用

利用升温红外分析和动态力学分析研究了纳米凹凸棒土改性热塑性聚氨酯(TPU)复合体系的氢键作用,探讨了复合体系中氢键的温度依赖性,求出了复合体系的氢键化程度、氢键解离能和解离熵。结果表明,纳米凹凸棒土改性TPU后,TPU中原本没形成氢键的自由羰基与纳米凹凸棒土表面富集的硅羟基形成了氢键,并且一定范围内羰基的氢键化程度、氢键解离能随着纳米凹凸棒土含量的提高而提高。复合体系氢键化程度随温度的升高急剧下降。     

Synthesis,Characterization, and Application Studies of Polyurethane Acrylate Thermoset Coatings: Effect of Hard Segment

The waterborne polyurethane acrylate coatings are smart option to reduce the environmental hazards. To evaluate the structure–property relationship, polyurethane acrylate coating dispersions were synthesized with aromatic and aliphatic hard segments. Furthermore, to evaluate the performance, dispersions were used to finish the cotton fabric. The dispersions were prepared by prepolymer method followed by emulsion polymerization in aqueous medium. The characterization of dispersions was performed by Fourier transform infrared, dynamic light scattering, atomic force microscopy, differential scanning calorimetry, and thermogravimetric analysis. In general, aliphatic hard segment has shown more appreciable results. But, thermal stability of aromatic polyurethane acrylate was more pronounced as inherent rigidity of aromatic diisocyanate dominates.     

Properties of Polyurethane Elastomers with Different Hard/Soft Segment Ratio

Three polyurethane elastomers (PU) containing different hard/soft (h/s) segment ratios were prepared. The PUs were characterized using Gel Permeation Chromatography (GPC), DSC, Wide Angle X-ray Diffraction (WAXD). Dynamic Mechanical Thermal Analysis (DMTA), and Stress-controlled rheometry. The surface properties were evaluated from contact angle measurements. The PUs were used as raw materials for solvent-based adhesives, whose adhesion properties were measured from T-peel tests of solvent-wiped polyvinyl chloride (PVC)/polyurethane adhesive joints. The increase in the amount of h/s segment ratio affected the structure and morphology of the PUs, reducing the degree of phase separation and the extent of the secondary interactions between polymer chains. The h/s segment ratio determined the thermal, mechanical, rheological and adhesion properties of the PUs.     

Properties of Polyurethane Elastomers with Different Hard/Soft Segment Ratio

Three polyurethane elastomers (PU) containing different hard/soft (h/s) segment ratios were prepared. The PUs were characterized using Gel Permeation Chromatography (GPC), DSC, Wide Angle X-ray Diffraction (WAXD). Dynamic Mechanical Thermal Analysis (DMTA), and Stress-controlled rheometry. The surface properties were evaluated from contact angle measurements. The PUs were used as raw materials for solvent-based adhesives, whose adhesion properties were measured from T-peel tests of solvent-wiped polyvinyl chloride (PVC)/polyurethane adhesive joints. The increase in the amount of h/s segment ratio affected the structure and morphology of the PUs, reducing the degree of phase separation and the extent of the secondary interactions between polymer chains. The h/s segment ratio determined the thermal, mechanical, rheological and adhesion properties of the PUs.     

Effects of Inert Diluent Segment and Hydrogen Bonding in Poly(styrene-co-methacrylamide) Copolymers

A series of random poly(styrene-co-methacrylamide) (PS-co-PMAAM) copolymers were prepared by free radical polymerization of styrene and methacrylamide monomers. The PS and PMAAM units of the copolymer do not have any specific interaction based on the Kwei equation and the infrared spectroscopy result, indicating that the styrene plays strictly as an inert diluent segment on the PMAAM main chain. This result offers an opportunity to enhance the miscibility and specific interaction between the amide group of PMAAM and the functional group of second polymer by reducing the strong self-association of the PMAAM.     

热塑性聚氨酯弹性体中的氢键作用-II.红外热分析

应用定量的红外热分析 ,研究了三种由聚四氢呋喃 ( Mn=2 0 0 0 )、4,4’-二苯基甲烷二异氰酸酯、N-甲基二乙醇胺或 1 ,4-丁二醇合成的 TPU中氢键化程度及其温度依赖性。并通过Van't Hoff作图 ,求出氢键解离的热焓和熵变化。