共混二异氰酸酯在聚氨酯弹性体中的应用

以二苯基甲烷二异氰酸酯(MDI)和甲苯二异氰酸酯(TDI)共混二异氰酸酯为原料,合成一系列聚氨酯弹性体制品,讨论了MDI/TDI摩尔比、扩链剂种类、聚醚多元醇种类等对聚氨酯弹性体制品性能的影响。结果表明,当MDI/TDI摩尔比为1∶1时,具有最高的伸长率,但拉伸强度和撕裂强度有所降低;以3,3′-二氯-4,4′-二苯基甲烷二胺(MOCA)作为扩链剂时,性能优于3,5-二甲硫基甲苯二胺(E-300)和1,4-丁二醇(BDO);采用聚醚DL-1000合成聚氨酯弹性体时,其拉伸强度和撕裂强度优于聚醚DL-2000,但伸长率降低。     

H12MDI型聚氨酯弹性体的制备及力学性能研究

以4, 4'–二环己基甲烷二异氰酸酯(H_(12)MDI)、聚醚多元醇等为主要原料,3, 3'–二氯–4, 4'–二氨基二苯基甲烷(MOCA)为扩链剂,采用预聚体法合成了聚氨酯弹性体,并研究了其力学性能。随NCO值提高,H_(12)MDI型聚氨酯弹性体的拉伸强度及硬度增加,伸长率降低;随MOCA量减小,拉伸强度和硬度均降低,伸长率提高。     

工程隔振用聚氨酯微孔弹性体的研制

以改性MDI(MM103C)、HDI三聚体(HI100)、组合聚醚多元醇YZ-2101、聚合物多元醇POP-36/28、聚醚多元醇330N、3,3′-二氯-4,4′-二氨基二苯基甲烷(MOCA)、1,4-丁二醇(BDO)和发泡剂等为原料,采用半预聚体法制备了工程隔振用聚氨酯微孔弹性体材料,研究了材料密度和硬段含量对微孔弹性体性能的影响。结果表明,随着密度的增加,微孔弹性体拉伸强度、断裂伸长率逐渐增大;随着硬段含量的增加,微孔弹性体的拉伸强度和静刚度逐渐升高,断裂伸长率逐渐减小,压缩永久变形率和动静刚度比先降低后升高,硬段质量分数40%时达到最低值,分别为6.5%和1.22。     

微孔聚醚型聚氨酯弹性体的制备与力学性能研究

以聚氧化丙烯三醇、高活性聚醚聚合物多元醇(HPOP)、二醇扩链剂、水及催化剂等助剂的混合物作为A组分,以聚四氢呋喃二醇(PTMG)、纯MDI和液化MDI为原料合成的半预聚体作为B组分,A组分和B组分按异氰酸酯指数1.1混合,制备微孔聚氨酯弹性体。讨论了预聚体的NCO含量、纯MDI与液化MDI质量比、二醇扩链剂种类和HPOP/聚醚三醇质量比对微孔弹性体力学性能的影响。结果表明,当预聚体NCO含量和纯MDI的用量增加时,微孔弹性体的硬度和拉伸强度增加;微孔弹性体的硬度随HPOP和1,4-丁二醇用量的增加而增加;当HPOP/聚醚三醇质量比为50∶50时,微孔弹性体的拉伸强度和断裂伸长率最高。     

聚氨酯弹性体软段对其力学性能的影响

先用4, 4'–二苯基甲烷二异氰酸酯(MDI)与不同相对分子质量不同种类低聚物多元醇合成预聚体,再以1, 4–丁二醇(BDO)为扩链剂制备聚氨酯弹性体,考察了软段对聚氨酯弹性体力学性能的影响。结果表明:当预聚体NCO含量相同时,聚酯型聚氨酯弹性体的力学性能整体优于聚醚型的,随低聚物多元醇相对分子质量的增加,聚氨酯弹性体的硬度、300%定伸应力、拉伸强度和撕裂强度降低,拉断伸长率增加,扩链系数为1.00时聚氨酯弹性体的力学性能最好;随预聚体NCO含量增加,聚氨酯弹性体的硬度、300%定伸应力、拉伸强度和撕裂强度提高,拉断伸长率下降。     

微交联对MDI型聚氨酯弹性体性能的影响

采用聚酯元醇、TMP和MDI-100制备聚氨酯弹性体,研究了交联点间相对分子质量、聚酯多元醇相对分子质量、交联方式等对弹性体性能的影响。研究表明随着交联点间相对分子质量的减小,聚氨酯弹性体的开模时间缩短,拉伸强度、回弹性、扯断伸长率及撕裂强度下降,100%及300%定伸应力提高,高温耐热性能提高;随着多元醇相对分子质量的增加,弹性体的回弹、拉伸强度、扯断伸长率及撕裂强度上升,100%定伸应力、300%定伸应力及磨耗下降;与MDI/BDO体系相比,交联对TDI/MOCA体系的力学性能影响较大。     

扩链剂与交联剂对NDI型聚氨酯弹性体性能的影响

用1,5-萘二异氰酸酯(NDI)和聚四氢呋喃醚二醇(PTMG)为原料合成了聚氨酯预聚体,以三羟基聚醚多元醇(330N)作为交联剂,1,4-丁二醇(BDO)作为扩链剂制备了NDI型聚氨酯弹性体,讨论了交联剂与扩链剂的不同羟基摩尔比对NDI型聚氨酯弹性体性能的影响。结果表明,随着三羟基聚醚多元醇含量的增加,NDI型聚氨酯弹性体软段玻璃化转变温度有所提高;三羟基聚醚多元醇的加入虽然使得聚氨酯弹性体的滞后损失峰值增加,但对常用温度范围的滞后损失影响不大,0～150℃温度范围内的储能模量降低;聚氨酯弹性体的拉伸强度与断裂伸长率随着三羟基聚醚多元醇含量的增加,呈先增加后下降的趋势变化,硬度则呈下降趋势。     

基于不同软段的聚氨酯弹性体耐热性能研究

分别以聚己内酯二醇(PCL)、聚碳酸酯二醇(PCDL)、聚己二酸-1,4-丁二醇酯二醇(PBA)以及聚四氢呋喃二醇(PTMG)为软段,4,4'-二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)为硬段,采用预聚体法合成4种基于不同软段的聚氨酯弹性体。通过机械性能测试、热失重分析、动态力学性能测试及不同温度下的力学性能分析,研究低聚物二醇种类对聚氨酯弹性体的力学性能和耐热性能的影响。结果表明,以聚酯多元醇作为软段制得的聚氨酯弹性体的耐热性要优于聚醚型;几种聚酯型聚氨酯弹性体中,PCL型聚氨酯弹性体的热稳定性以及不同温度下的力学性能保持率最高,耐热性最好;动态力学性能分析表明,在高弹态平台区PCL型聚氨酯的损耗因子较小,动态内生热较小,且储能模量下降较缓慢,动态力学性能最好。     

聚氨酯微孔弹性体加速老化评估及使用寿命研究

以改性MDI和聚醚多元醇为基本原料制备聚氨酯微孔弹性体,通过50℃、70℃和90℃水热老化试验,分析在特定老化温度条件下,聚氨酯微孔弹性体力学性能随时间的变化情况。结果表明,聚氨酯微孔弹性体的拉伸强度、断裂伸长率、硬度和压缩静刚度等性能在水热老化试验前期有短时间增加,然后都随时间减小。在较高温度的水热老化试验中,材料的力学性能降低较快。筛选压缩静刚度作为表征材料老化过程的性能指标,利用阿伦尼乌斯方程建立使用温度与寿命之间的模型,推算聚氨酯弹性体材料使用寿命。     

室温固化型MDI体系聚氨酯弹性体力学性能的研究

以不同结构多元醇和4,4′-二苯基甲烷二异氰酸酯(MDI-100)合成预聚体,再与不同扩链剂反应制备室温固化MDI型聚氨酯弹性体。讨论了多元醇种类、扩链剂种类、扩链系数、稀释剂用量、催化剂种类对聚氨酯弹性体力学性能的影响。结果表明,结构规整的多元醇制备的聚氨酯弹性体综合性能较好;二醇类扩链剂1,4-丁二醇(1,4-BDO)和对苯二酚二羟基乙基醚(HQEE)制备的弹性体性能较好,操作工艺可行;扩链系数以0.85~1.0为宜;适宜稀释剂质量分数为5%~10%;MDI室温固化体系的催化剂可选用HDcat。     

聚醚型高硬度聚氨酯弹性体的研制

采用聚氧化丙烯多元醇、二醇扩链剂和多异氰酸酯为原料，用一步法工艺制得一系列高硬度聚氨酯弹性体。讨论了多元醇组分平均每个羟基所对应的链段的相对分子质量(MOH)、平均官能度以及异氰酸酯种类对高硬度聚氨酯弹性体性能的影响。结果表明，采用液化MDI或粗MDI与聚氧化丙烯醚配合使用可以制得邵D硬度大于65的聚醚型高硬度聚氨酯弹性体。     

城市轨道交通用聚氨酯微孔弹性减振垫板的研制

以聚四氢呋喃二醇(PTMG)、聚醚三醇EP-330N、二苯基甲烷二异氰酸酯(MDI)、液化MDI、三羟甲基丙烷(TMP)、乙二醇(EG)、催化剂A33和水等为原料,采用预聚法合成了聚氨酯微孔弹性体材料。考察了A组分聚醚PTMG/EP-330N配比、扩链剂/交联剂配比及B组分游离NCO含量对材料性能的影响,并对比了用聚氨酯微孔弹性材料与现有的橡胶发泡材料制备的减振垫板的产品性能。结果表明:适当提高材料中EP-330N、TMP含量或提高NCO基含量均可提高材料的力学强度、压变性能与耐油性能;使用聚氨酯微孔弹性体材料制备的减振垫板具有更好的抗疲劳性能。     

无溶剂型单组分聚氨酯胶粘剂的研制

以聚醚二元醇(PPG)、改性MDI(4,4′-二苯基甲烷二异氰酸酯)、PAPI(多亚甲基多苯基多异氰酸酯)、1,4-BDO(1,4-丁二醇)和环保型PU潜固化剂等为主要原料,采用预聚体法制得无溶剂型单组分聚氨酯(PU)胶粘剂。研究结果表明:该胶粘剂的玻璃化转变温度(Tg)为-26.9℃;当R=n(-NCO)/n(-OH)=6.5~9.0、w(-NCO)=3.5%、w(环保型PU潜固化剂)=3%和聚醚二元醇是相对分子质量为1 000的PPG210时,PU胶粘剂的黏度适中、固化速率较快和可操作性良好,并且其强度和韧性俱佳。     

Phase separation in segmented polyurethanes derived from mixtures of polyether polyols with different functionality

A series of segmented polyurethanes containing 60 wt° of hard segments (HS) was prepared from MDI (4,4-diphenylmethane diisocyanate) ethylene glycol and mixtures of a polyoxyethylene end-capped polyoxypropylene triol and a polyoxyethylene end-capped polyoxypropylene diol. The effects of the content of polyether diol in polyether polyols on phase separation and properties was investigated by dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and investigation of tensile properties. The DSC and DMA results indicate that the polyurethane derived from only polyether triol exhibits obvious phase separation and that the HS is immiscible with the SS, but that the HS is compatible with the HS for the polyurethane derived from polyether diol. As the content of polyether diol increases, the compatibility between HS and SS increases. As the content of polyether diol increases, the tensile strength. elongation. toughness and tear resistance of the polyurethanes increases. but their moduli decrease. The modulus-temperature dependence in the temperature region of –30 to 65 °C increases as the polyether diol content increases.     

Elasticity behavior of swollen polyurethane networks

A series of polyurethane networks were prepared by reacting MDI (4,4′-diphenylmethane diisocyanate) with various mixtures of poly(oxyethylene) end-capped poly(oxypropylene) triol and diol. The uniaxial compressive properties of the polyurethane networks both in equilibrium swelling in toluene and in a dried state were measured at 27 °C. The compressive stress-strain data were analyzed according to equations based on the Gaussian theory of elasticity. Deviations from the Gaussian behavior were observed; however, as the polyether diol content increased, deviations from the Gaussian behavior decreased. The interaction parameters between the polyurethane networks and toluene at an equilibrium state were analyzed by the Flory-Huggins equation. As the polyether diol content increased, the interaction parameter, χ, increased due to the increasing content of the poly(oxyethylene) unit and urethane group concentration. With increasing polyether diol content, polyurethane networks approached phantom behavior more closely.     

Effect of formulation on properties and morphology of polyurethane elastomers

A model polyurethane elastomers system has been used to study the relationships between chemical formulation, polymer physical structure and mechanical properties. The elastomers were made from formulations comprising a polyether polyol blend (diol plus triol), a chain extender blend (1,4 butane diol plus 1,1,1-trimethylol propane) and 4,4′-di-isocyanate diphenylmethane. The morphologies of the elastomers were investigated in detail, mainly by means of small angle X-ray scattering techniques. It was confirmed that the polyurethane systems examined comprised domains 50 to 100 Å in size and spaced around 100 to 200 Å apart. A complete decription of the polyurethane morphology has been made in terms of the volume fraction of domains present, the average domain size and the average domain–domain separation. The results suggest that, whilst it is possible to correlate, in general, formulation changes with variations in the elastomer morphology, it seems that direct correlations between physical structure and mechanical properties are not very meaningful in the present model system. However, it is clear that knowledge of the morphology is of considerable importance in interpreting the effects of formulation on observed properties.     

丙烯酸酯改性交联型水性聚氨酯胶黏剂

以异佛尔酮二异氰酸酯(IPDI)、聚己二酸-1,4-丁二醇酯二醇(PBA)为主要原料、三聚氰胺为交联剂,合成了双键封端的交联型水性聚氨酯,再经过原位聚合制备了丙烯酸酯改性水性聚氨酯胶黏剂。利用FTIR、XRD、DLS、DTA、电子拉力机、邵氏硬度计等对材料结构与性能进行了表征。通过调节水性聚氨酯与丙烯酸酯的质量比、三聚氰胺的添加量,对产品性能进行了优化。结果表明,当水性聚氨酯与丙烯酸酯质量比为6∶4、三聚氰胺占水性聚氨酯质量为0.53%时,胶黏剂发生5%质量分数的降解温度可达到312℃,吸水率仅为4.69%,T-型剥离强度为5.3 kN/m。     

喷涂聚氨酯-脲-酰亚胺弹性体的合成及应用

以均苯四甲酸酐(PMDA)、碳化二亚胺改性MDI(L-MDI)、聚醚多元醇、蓖麻油、端氨基聚醚、小分子二胺等合成了喷涂聚氨酯-脲-酰亚胺弹性体。通过ATR、TGA、DMA、SEM、力学性能等测试,发现当A组分中NCO基质量分数在13%左右,多元醇(GEP)/蓖麻油(CTO)质量比为80∶20时,产品具有较好的力学性能和施工性能,且PMDA含量增加对产品耐热性有改善,储能模量、损耗模量也均有提高,但对损耗因子影响不明显。该弹性体应用于卫浴产品获得了良好的效果。