混合大二醇基聚氨酯弹性体/环氧树脂互穿网络聚合物的研究

以α,ω-双(γ-羟丙基)聚二甲基硅氧烷(BHPDMS)和聚氧四甲基二醇(PHMO)混合大二醇作为软链段,首先通过两步溶液聚合法合成了-NCO封端的混合大二醇基聚氨酯(PU)弹性体预聚物(PUT);然后以PUT和环氧树脂(EP)预聚物为原料、1,3-双(γ-氨丙基)-1,1,3,3-四甲基二硅氧烷(BATS)为交联剂,采用同步溶液聚合法合成了PUT/EP互穿聚合物网络(PUT/EP I PN)。使用傅里叶红外光谱(FT-I R)法、动力学分析(DMA)法和扫描电子显微镜(SEM)法,对PUT和PUT/EP I PN进行分析和表征,并对其力学性能和表面疏水性进行测试。实验结果表明,PUT/EP I PN中不存在宏观相分离状态,仅发生微观相分离状态;当PUT/EP I PN中w(PUT)=50%时,PUT/EP I PN具有优异的综合力学性能和表面疏水性。     

大二醇软链段混合比对聚氨酯弹性体的性能影响

以α,ω-双(γ-羟丙基)聚二甲基硅氧烷(BHPDMS)和聚氧四甲基二醇(PHMO)混合大二醇作为软链段,以1,4-丁二醇(BDO)为扩链剂,采用两步溶液聚合法合成了大二醇基芳香聚氨酯(PU)弹性体,其中w(硬链段)=40%。使用傅里叶红外光谱(FT-IR)法和差示扫描量热法(DSC),研究了混合大二醇中BHPDMS与PHMO的质量比对该PU弹性体的结构形态和性能的影响。结果表明,当混合大二醇中w(PHMO)=40%-60%时,所得PU弹性体具有优异的综合力学性能和表面疏水性。     

用混合扩链剂合成的聚氨酯弹性体

研究了混合扩链剂对MDI体系浇注型聚氨酯弹性体的工艺性能及其物理性能的影响。同时考察了不同软段、硬段结构对其性能的影响，通过TGA分析对其热性能进行了表征。     

二醇扩链剂对聚醚聚氨酯弹性体性能的影响

研究了以乙二醇、一缩二乙二醇、1,4-丁二醇和1,6-己二醇作为扩链剂对聚醚聚氨酯弹性体性能的影响。结果表明,扩链剂链长越短,弹性体的微相分离程度和力学性能越好;以BDO扩链为例,随其用量的增加,弹性体的性能提高,达到一定值后再增加用量性能反而下降;混合扩链剂有助于聚氨酯弹性体综合性能的提高。     

扩链剂对IPDI基透明聚氨酯弹性体的影响

采用异佛尔酮二异氰酸酯(IPDI)和不同结构的扩链剂、多元醇合成了透明聚氨酯弹性体，通过DSC、TG、WAXD等研究了聚氨酯弹性体的形态结构和力学性能、热稳定性及光学透明性。结果表明，扩链剂结构对聚氨酯弹性体形态结构和力学性能、热稳定性及光学透明性有很大影响。降低扩链剂长度有利于微晶的长大、微相分离程度及力学性能的提高；增加扩链剂用量，聚氨酯弹性体的微相分离程度、微晶尺寸、力学性能及热稳定性能提高；硬段含量对聚氨酯弹性体光学透明性的影响不明显。     

以小分子二醇为扩链剂的聚氨酯弹性体的制备及性能

采用小分子二醇为扩链剂制备了具有不同性能的聚氨酯弹性体（PUE）材料,研究了小分子二醇用量对聚氨酯弹性体性能的影响。结果表明：对于数均相对分子质量（^-Mn）为2000的聚酯多元醇CMA-24和聚己内酯多元醇PCL-220N而言,随着小分子二醇用量的增加,所合成的PUE断裂伸长率下降,硬度及100％或300％定伸强度增加,玻璃化转变温度（Tg）升高,阻尼因子tanδ最大值越来越低;对于^-Mn为3000的聚酯多元醇CMA-66而言,随着小分子二醇用量的增加,所合成的PUE的硬度、断裂伸长率下降,当小分子二醇（乙二醇、1,4-丁二醇、1,6-己二醇（HDO））与CMA-66的物质的量比为1：1及2：1时,所制得PUE有2个Tg峰,当比值为3：1及4：1时,Tg为1个峰。当HDO与CMA-66的物质的量比由1：1增大到4：1时,所制PUE由完全不透明转变为透明。     

扩链剂对聚氨酯弹性体力学性能的影响

综述了各种扩链剂对聚氨酯弹性体力学性能的影响,发现两种或两种以扩链剂的协同作用能很好地改善聚氨酯弹性体的力学性能。     

不同扩链剂对浇注型聚氨酯弹性体的影响

以甲苯二异氰酸酯(TDI)和聚四亚甲基二醇(PTMG)为原料合成聚氨酯(PU)预聚体,分别用3,3′–二氯–4,4′–二氨基二苯甲烷(MOCA)和二乙基甲苯二胺(DETDA)为扩链剂制备了一系列聚氨酯弹性体(PUE),研究了扩链系数、掺杂BDO(1,4–丁二醇)以及MOCA与DETDA混用对PUE性能的影响。结果表明:随扩链系数的增加,MOCA–PU和DETDA–PU的强度和模量先增加后减小,断裂伸长率先减小后增大;随BDO用量的增加,MOCA–PU和DETDA–PU的硬度、强度和模量呈下降趋势,断裂伸长率和凝胶时间呈上升趋势;使用混合扩链剂时,提高扩链剂中MOCA含量,DETDA–PU的硬度、拉伸强度和撕裂强度呈下降趋势,断裂伸长率和凝胶时间呈上升趋势。     

Synthesis and properties of waterborne polyurethane adhesives: effect of chain extender of ethylene diamine,butanediol, and fluoro-butanediol

Waterborne polyurethane (WBPU) adhesives were prepared using poly(tetramethylene oxide glycol), 4,4’-dicyclohexylmethane diisocyanate (H₁₂MDI), hydrophilic agent dimethylol propionic acid and chain extender of 2,2,3,3-tetrafluoro-1,4-butanediol (TFBD), ethylene diamine (EDA), and 1,4-butanediol. All three chain extenders have been used as single and mixed (different ratio) content during synthesis, and the effect of chain extender and their content to the properties of tensile strength, Young’s modulus, water swelling (%), and adhesive strength was investigated. The adhesive strength value was higher using EDA as a single-chain extender; however, the potentiality of adhesive strength under water was improved using mixed-chain extenders of EDA and TFBD in WBPU adhesives. The maxima potentiality was observed with 6.31 mole% TFBD and 2.10 mole% EDA in WBPU adhesives.     

小分子扩链剂对醇溶性聚氨酯性能的影响

采用异佛尔酮二异氰酸酯(IPDI)、聚醚二元醇( N220)以及不同结构的小分子二元醇扩链剂为主要原料,合成了一系列具有不同结构的醇溶性聚氨酯.示差扫描量热和热重测试显示,以一缩二乙二醇为扩链剂的聚氨酯Tg最低,耐热性最差;以乙二醇、1,4-丁二醇、己二醇为扩链剂的聚氨酯Tg依次上升;耐热性能依次降低透射电镜测试表明,...     

硬段对热塑性聚氨酯弹性体结构及性能的影响

以实验室自制聚己二酸乙二醇酯二醇PEA为软段,二苯基甲烷-4,4’二异氰酸酯(MDI)为硬段,分别采用乙二醇(EG、1,4-丁二醇)、BOD和1,6-己二醇、HG为扩链剂,经预聚体法合成了硬段不同的聚氨酯弹性体。研究了硬段结构和硬段含量对弹性体硬度及力学性能的影响。采用旋转流变仪研究了弹性体在降温条件下的非等温结晶过程。结果表明,当硬段含量相同时,BDO-TPU结晶性能最好,拉伸强度最大;HG-TPU断裂伸长率最好。在BDO-TPU体系中,随硬段含量增加,材料硬度和强度增加,伸长率减小;结晶起始温度逐渐增大,结晶性能增强。     

原料对聚氨酯弹性体透明性的影响

研究了采用不同类型的异氰酸酯、聚合多元醇及扩链剂合成透明聚氨酯（PU）弹性体，详细讨论分析了异氰酸酯的种类、多元醇的种类及分子量、扩链剂的类型及结构特点、微量水分等对PU透明性的影响。结果表明，采用脂环族异氰酸酯IPDI或脂肪族异氰酸酯HDI，分子量为1000－2000的聚醚二元醇PTMEG和丁二醇BOD类扩链剂制备出的PU具有优异的透明性；同时结合PU的力学性能，进一步明确透明PU的原料及配方，结果显示：n（IPDI）：n（PTMEG1000）：n（1，4－BOD）＝2：1：1时的PU具有最好的综合性能。     

Enhancing mechanical and shape memory properties of polylactide/polyamide elastomer blends via reactive blending with a chain extender

The structure and properties of incompatible polylactide (PLA)/polyamide elastomer (PAE) blends were tailored by a chain extender specifically the styrene–glycidyl acrylate copolymer Joncryl ADR4368 (ADR). Various PLA/PAE/ADR blends with different compositions were prepared by melt blending, and their morphology, crystallization behavior, and mechanical and the shape memory properties were systematically investigated. The results showed a uniform dispersion of PAE particles in the PLA matrix for the PLA blends with a reduction in particle size upon the addition of ADR. The crystallization of PLA was retarded, which was confirmed by a decrease in the melt crystallization temperature and an increase in cold crystallization temperature in the PLA/PAE/ADR blends. Rheological analysis showed an improvement in the melt elasticity of the PLA/PAE binary blend due to the presence of ADR, possibly attributed to the formation of long-chain-branched copolymers at the interface. Notably, the PLA/PAE/ADR blend exhibited superior toughness, featuring an elongation at break of 288% and a notched impact strength of 37 kJ·m⁻², along with a high shape memory fixation rate and recovery rate when the ADR content was 1 wt%. Furthermore, the underlying toughening mechanism was elucidated. This work may offer an industrially scalable relevant model to fabricate high-performance PLA materials.     

MDI基热塑性聚酯型聚氨酯弹性体性能的研究

以4,4′-苯基甲烷二异氰酸酯（MDI）、聚己二酸丁二醇酯二醇（PBA）、1,4-丁二醇（BDO）为原料,采用一步法合成热塑性聚氨酯弹性体（TPU）。在n（—NCO）/n（—OH）（R值）恒定条件下,研究了PBA相对分子质量、BDO添加量与TPU性能关系,并由红外光谱、热重、X射线衍射分别表征了TPU的结构、热性能和结晶特性。研究发现：R值、BDO量和MDI量恒定时,PBA的相对分子质量越高,TPU的拉伸强度、断裂伸长率均呈增加趋势;R值恒定,以相对分子质量3 000的PBA为原料,TPU的拉伸强度、断裂伸长率均随BDO添加量的增加而增加;TPU的热分解温度高于300℃,结晶特性显著。     

Poly(dimethylsiloxane)/poly(hexamethylene oxide) mixed macrodiol based polyurethane elastomers. I. Synthesis and properties

The compatibilizing effect of poly(hexamethylene oxide) (PHMO) on the synthesis of polyurethanes based on α,ω‐bis(6‐hydroxyethoxypropyl) poly(dimethylsiloxane) (PDMS) was investigated. The hard segments of the polyurethanes were based on 4,4′‐methylenediphenyl diisocyanate (MDI) and 1,4‐butanediol. The effects of the PDMS/PHMO composition, method of polyurethane synthesis, hard segment weight percentage, catalyst, and molecular weight of the PDMS on polyurethane synthesis, properties, and morphology were investigated using size exclusion chromatography, tensile testing, and differential scanning calorimetry (DSC). The large difference in the solubility parameters between PDMS and conventional reagents used in polyurethane synthesis was found to be the main problem associated with preparing PDMS‐based polyurethanes with good mechanical properties. Incorporation of a polyether macrodiol such as PHMO improved the compatibility and yielded polyurethanes with significantly improved mechanical properties and processability. The optimum PDMS/PHMO composition was 80 : 20 (w/w), which yielded a polyurethane with properties comparable to those of the commercial material Pellethane™ 2363‐80A. The one‐step polymerization was sensitive to the hard segment weight percentage of the polyurethane and was limited to materials with about a 40 wt % hard segment; higher concentrations yielded materials with poor mechanical properties. A catalyst was essential for the one‐step process and tetracoordinated tin catalysts (e.g., dibutyltin dilaurate) were the most effective. Two‐step bulk polymerization overcame most of the problems associated with reactant immiscibility by the end capping of the macrodiol and required no catalysts. The DSC results demonstrated that in cases where poor properties were observed, the corresponding polyurethanes were highly phase separated and the hard segments formed were generally longer than the average expected length based on the reactant stoichiometry. Based on these results, we postulated that at low levels (∼ 20 wt %) the soft segment component derived from PHMO macrodiol was concentrated mainly in the interfacial regions, strengthening the adhesion between hard and soft domains of PDMS‐based polyurethanes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 2026–2040, 2000     

Effect of chain extender on microphase structure and performance of self-healing polyurethane and poly(urethane-urea)

In this work, four aliphatic chain extenders, hexanediol (HDO), hexane diamine (HDA), cystamine (CY), and cystine dimethyl ester (CDE), were chosen to synthesize four kinds of polyurethane and poly(urethane-urea)s (PUs), respectively. HDO extended polyurethanes, HDA extended poly(urethane-urea), CY extended poly(urethane-urea), and CDE extended poly(urethane-urea) were denoted as OPU, APU, CPU, and SPU, respectively. The effect of chain extender type on microphase structure and performance of four PUs was investigated. Our research showed that mechanical strength increased in the following order: OPU < SPU < CPU < APU, and self-healing performance increased in the opposite direction. This result is attributed to the increasing degree of microphase separation: OPU < SPU < CPU < APU. The optimal sample SPU has not only excellent mechanical properties (tensile strength of 27.1 MPa and elongation at break of 397.7%), but also exhibits superior self-healing performance (self-healing efficiencies of 95.3% and 93.5% based on tensile strength and elongation at break). The moderate degree of microphase separation between the soft segments and the hard segments, the introduction of disulfide bonds and low degree of hydrogen bonding are responsible for preparing a polyurethane or poly(urethane-urea) system with high mechanical strength and excellent self-healing performance simultaneously. This work provides useful information for us to develop self-healing polyurethane or poly(urethane-urea) materials in the future.