Preparation and Characterization of Footwear Soling Materials Based on Biodegradable Polyurethane

The aim of this research work is to prepare biodegradable polyurethane composites and study their physical, mechanical, thermal, and biodegradation properties. Rigid biodegradable polyester-based polyurethane was synthesized by reacting excess of isocyanate with poly(ε-caprolactone)diol to obtain prepolymer which was then reacted with chain extender. The polyurethane composites are prepared with nanoclay and titanium(IV)oxide nanopowder in different concentrations, and polyurethane containing 2% w/w of nanopowder had shown better properties. Biodegradation studies showed that the developed polyurethane materials when used as shoe soles will retain their strength while storage and use, but will decompose only after disposal into the environment.     

不同结构水性聚氨酯分散体的合成与性能研究

用不同结构不同分子质量的聚酯多元醇合成一系列水性聚氨酯分散体,探讨了其力学性能、黏度、粘附力和贮存稳定性,还分析了结晶性、扩链剂和硬段含量对水性聚氨酯性能的影响.结果表明,用PBA和PHA合成的水性聚氨酯具有较好的性能,适度的结晶性有利于提高粘附力,扩链交联剂在一定的比例范围才能保持分散液的稳定性,40%～46%硬段含量可以保证水性聚氨酯既有较好的力学性能和黏度,又有满足使用要求的干燥速度.     

Synthesis and characterization of chlorine‐containing flame‐retardant polyurethane nanocomposites via in situ polymerization

We have developed flame‐retardant polyurethanes (FRPUs) and polyurethane (PU) nanocomposites via in situ polymerization. Three series of thermoplastic elastomeric PUs were synthesized to investigate the effect of incorporating 3‐chloro‐1,2‐propanediol (CPD) and nanoclay on mechanical, thermal properties, and also resistance to burning. PU soft segments were based on poly(propylene glycol). Hard segments were based on either CPD or 1,4‐buthane diol (BDO) in combination with methyl phenyl di‐isocyanate named PU or FRPU, respectively. In the third series, CPD was used as chain extender also nanoclay (1% wt) and incorporated and named as flame‐retardant polyurethane nanocomposites (FRPUN). Mechanical properties and LOI of PUs and nanocomposites have been evaluated. Results showed that increasing the hard segment (chlorine content) leads to the increase in flame retardancy and burning time. Addition of nanoclay to CPD‐containing PUs leads to obtain self‐extinguish PUs using lower CPD contents, higher Young's modulus, and strength without any noticeable decrease in elongation at break. Investigation of the TGA results showed that copresence of nanoclay and chlorine structure in the PU backbone can change thermal degradation pattern and improve nanocomposite thermal stability. X‐ray diffraction and transmission electron microscopy studies confirmed that exfoliation and intercalation have been well done. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

New Polyurethane Elastomers with Enhanced Thermal Stability

A series of polyurethane elastomers with enhanced thermal stability was prepared and their physical and thermal properties were studied. For this purpose in the first step, an excess amount of methylene diphenyl diisocyanate was reacted with poly(tetramethylene ether) glycol to produce isocyanate-terminated polyurethane pre-polymer. In the second step, a new imide-based diol chain extender was synthesized via reaction of benzophenonetetracarboxylic dianhydride with 5-amino-1-naphthol. Finally, reaction of the pre-polymer with chain extender resulted in preparation of polyurethane elastomers. Presence of imide unit in the polymer backbone improved their properties and enhanced thermal stability of polyurethane.     

Evaluation of disulfide chain extender effect on the mechanical properties of unsaturated polyurethane‐urea networks

4‐Aminophenyl disulfide and bis(4‐aminophenyl)methane chain extenders containing hydroxyl‐terminated polybutadiene‐based polyurethane‐ureas are prepared one‐shot to explore the effect of the chain extender structure on the elastomers mechanical properties. However, the results revealed that the participation of the disulfide chain extender in side reactions like thiol‐ene and proton abstraction prevented disulfide metathesis reaction due to decomposing chain extender in the polyurethane‐urea matrix. Also, these side reactions improved the phase mixing via chemical crosslinking between polyurethane‐ureas soft and hard segments, too. Tensile test results showed higher stress strength of the elastomers in the presence of the disulfide chain extender in comparison with the nondisulfide bond containing elastomers. This result was in agreement with the observed result in dynamical mechanical analysis. Dynamic mechanical analysis results established that the absence of the disulfide bond in the polyurethane‐urea matrix led to the higher viscous modulus. The swelling test revealed chemical crosslinking increased in the presence of the disulfide bond. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46309.     

Synthesis and investigation of properties of thiacalix[4]arene‐based polyurethane elastomers

A series of polyurethane elastomers (PUEs) derived from three thiacalix[4]arene derivatives (TC4As), namely p‐tert‐butylthiacalix[4]arene, tetrasodium thiacalix[4]arenetetrasulfonate and thiacalix[4]arenetetrasulfonic acid, as a portion of chain extender in a mixture with glycerol were synthesized. The effects of the chemical structure of TC4As used as chain extenders on the various properties of the prepared PUEs were investigated and compared with PUE extended with only glycerol as chain extender using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), scanning electron microscopy and a universal tensile tester. Moreover, the effect of the introduction of TC4As as a portion of chain extender on the hydrophobicity of the PUEs was also evaluated. DSC, FTIR spectroscopy and XRD revealed that the degree of phase separation and crystallinity in TC4A‐based PUEs was much higher than that of the glycerol‐based ones. Thus, it was concluded that the presence of TC4As in TC4A‐based PUEs seems to favour the formation of a more ordered structure due to an increase in the degree of phase separation. The TGA results also showed that, with incorporation of TC4As into the polyurethane backbone, the thermal stability of PUEs was improved. © 2014 Society of Chemical Industry     

The effect of soft‐segment structure on the properties of novel thermoplastic polyurethane elastomers based on an unconventional chain extender

Thermoplastic polyurethane elastomers (TPUs) are now widely used because of their excellent properties that include high tensile and tear strength, and good abrasion, impact and chemical resistance. TPUs are multiblock copolymers with alternating sequences of hard segments composed of diisocyanates and simple diols (chain extenders) and soft segments formed by polymer diols. Commonly used hard segments for TPUs are derived from 4,4′‐diphenylmethane diisocyanate (MDI) and aliphatic diols. The aim of our research was to examine the possibility of obtaining TPUs with good tensile properties and thermal stability by using an unconventional aliphatic‐aromatic chain extender, containing sulfide linkages. Three series of novel TPUs were synthesized by melt polymerization from poly(oxytetramethylene) diol, poly(ε‐caprolactone) diol or poly(hexane‐1,6‐diyl carbonate) diol of number‐average molecular weight of 2000 g mol^?1 as soft segments, MDI and 3,3′‐[methylenebis(1,4‐phenylenemethylenethio)]dipropan‐1‐ol as a chain extender. The structure and basic properties of the polymers were examined using Fourier transfer infrared spectroscopy, X‐ray diffraction, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Shore hardness and tensile tests. It is possible to synthesize TPUs from the aliphatic‐aromatic chain extender with good tensile properties (strength up to 42.6 MPa and elongation at break up to 750%) and thermal stability. Because the structure of the newly obtained TPUs incorporates sulfur atoms, the TPUs can exhibit improved antibacterial activity and adhesive properties. Copyright © 2011 Society of Chemical Industry     

Effect of chain extender structure on the properties and morphology of polyurethanes based on H12MDI and mixed macrodiols (PDMS–PHMO)

The effect of chain extender structure on properties and morphology of α,ω‐bis(6‐hydroxyethoxypropyl) polydimethylsiloxane (PDMS) and poly(hexamethylene oxide) (PHMO) mixed macrodiol‐based aliphatic polyurethane elastomers was investigated using tensile testing, differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). All polyurethanes were based on 50 wt % of hard segment derived from 4,4′‐methylenecyclohexyl diisocyanate (H₁₂MDI) and a chain extender mixture. 1,4‐Butanediol was the primary chain extender, while one of 1,3‐bis(4‐hydroxybutyl)tetramethyldisiloxane (BHTD), 1,3‐bis(3‐hydroxypropyl)tetramethyldisiloxane (BPTD), hydroquinonebis(2‐hydroxyethyl)ether (HQHE), 1,3‐bis(3‐hydroxypropyl)tetramethyldisilylethylene (HTDE), or 2,2,3,3,4,4‐hexafluoro‐1,5‐pentanediol (HFPD) each was used as a secondary chain extender. Two series of polyurethanes containing 80 : 20 (Series A) and 60 : 40 (Series B) molar ratios of primary and secondary chain extenders were prepared using one‐step bulk polymerization. All polyurethanes were clear and transparent and had number‐average molecular weights between 56,000 and 122,100. Incorporation of the secondary chain extender resulted in polyurethanes with low flexural modulus and high elongation. Good ultimate tensile strength was achieved in most cases. DSC and DMTA analyses showed that the incorporation of a secondary chain extender disrupted the hard segment order in all cases. The highest disruption was observed with HFPD, while the silicon‐based chain extenders gave less disruption, particularly in Series A. Further, the silicon chain extenders improved the compatibility of the PDMS soft segment phase with the hard segment, whereas with HFPD and HQHE, this was not observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2979–2989, 1999     

含氟二元胺为扩链剂的聚氨酯弹性体的合成和表征

以2,2-双(4-羟基苯基)六氟丙烷(全氟双酚A)为原料合成了2,2-双[4-(4-氨基苯氧基)苯基]六氟丙烷(BAPF6P),以此二元胺为扩链剂制备了一系列不同硬段含量的含氟聚氨酯弹性体(FPUE)。通过FTIR、TG、EA、WAXD、1H-NMR、DMA分析及拉伸试验,对BAPF6P和由其制备的FPUE的结构和性能进行了研究。结果表明,所得产物BAPF6P的结构与预期设计相符;由于FPUE的硬段间的强氢键作用和偶极效应,使得微区中部分链段排列有序形成微晶结构;随着硬段含量的提高,Tg逐渐升高,FPUE的耐寒性能逐渐降低,而耐热氧化性逐渐提高;FPUE的热分解温度在200℃以上,具有良好的耐热性能及优异的力学性能,BAPF6P是一个好的聚氨酯扩链剂。     

高固含量双组分混合聚酯型水性聚氨酯的合成

以异佛尔酮二异氰酸酯(IPDI)为硬段、混合双组分聚酯二元醇和1,4-丁二醇(BDO)为软段、二羟甲基丙酸(DMPA)为亲水扩链剂、三乙胺(TEA)为中和剂和乙二胺(EDA)为后扩链剂等,采用预聚体分散法合成了系列高固含量的水性聚氨酯(WPU)乳液。以固含量、黏度和吸水率等为衡量指标,比较了不同聚酯二元醇的混合效果。结果表明:当混合聚酯中n(PBA或PCDL)∶n(PEBA或PCDL)=1∶1、w(DMPA)≈3.4%(相对于预聚体而言)、n(-NCO)∶n(-OH)=1.03∶1和中和度为96%时,由PBA2000/PCDL2000混合聚酯二元醇制取的WPU乳液,其固含量较高(48.70%)、黏度最低(542 mPa.s)且综合性能相对较好。     

Silk‐inspired polyurethane containing GlyAlaGlyAla tetrapeptide. I. Synthesis and primary structure

Biomedical polyurethane (PU) and silk fibroin have similar molecular architecture in their primary and aggregate structure, both of which have imido bonds and microphase separation, and they have been employed as scaffold materials for biomedical applications. As the featured peptide sequence of silkworm silk protein, GlyAlaGlyAla (GAGA) tetrapeptide was synthesized by using traditional liquid‐phase peptide synthesis method with Boc‐protected alanine and glycine as starting materials, and was transformed to its derivative with two end‐amido groups. The derivative was incorporated into the backbone of the classical synthetic copolyurethane as a chain extender to form a silk‐inspired polyurethane. Elemental analysis showed the nitrogen content in the silk‐inspired PU was higher than that in the butanediol‐extended PU but lower than the theoretical value, indicating the chain extender containing GAGA was partially incorporated into the PU chain. The results from ¹H‐nuclear magnetic resonance, Fourier transform infrared spectra, Raman scattering spectra and pyrolysis‐gas chromatography/mass spectrometry qualitatively identified the primary structure of the silk‐inspired polyurethane. This concept and strategy may allow the fabrication of a new class of thermoplastic polyurethane elastomer to mimic the structure and properties of silk fibers if in fiber form, which combines traditional synthetic polymer chains with peptide sequences. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

四重氢键扩链剂的合成及其对聚氨醋性能的影响

合成了可通过四重氢键自聚的含2-脲-4[1H]-嘧啶酮(2-ureido-4 [1H] -pyrimidone,Upy)结构的扩链剂2-甲基-Upy基-1,3-丙二醇.以此二元醉结合不同比例的1,4-丁二醇为扩链剂,合成一系列不同Upy侧基含量的聚氨醋弹性体(PU-Upy).通过FT-IR、1H-NMR、TG、DMA分...     

软段含离子基团的阴离子型水性聚氨酯胶粘剂的研究(Ⅱ)——硬段结构的影响

以含有不同离子基团的聚酯多元醇为软段,采用丙酮法合成了一系列水性聚氨酯乳液。研究了不同硬段结构和硬段含量和扩链剂对其干膜物理机械性能和吸水率的影响。     

双组分水性聚氨酯涂料的合成与表征

随着环境法规对涂料的挥发性有机化合物（VOC）含量的限制，高性能与低VOC含量相结合的双组分水性聚氨酯涂料成为涂料工业发展的趋势。采用三羟甲基丙烷（TMP）为扩链剂合成具有交联结构的水性聚氨酯分散体多元醇，与多异氰酸酯固化剂组成双组分水性聚氨酯涂料。研究发现双组分涂膜的机械性能和外观是由合成的水性聚氨酯多元醇的扩链剂（TMP）含量，中和度，中和工艺和双组分涂料的配比等决定的。当扩链剂含量为2％－4％，中和度为100％，NCO:OH=1．0－1．2时所得双组分水性聚氨酯涂膜外观好，快干，硬度高和施工方便。     

Synthesis of waterborne polyurethane containing alkoxysilane side groups: Study on spacer linkages

Environmentally friendly waterborne polyurethanes (WPUs) modified by moisture‐curable alkoxysilane have been much studied nowadays. In this work, a new diol‐bearing pendant urea‐propyl trimethoxysilane (APD‐Si) was synthesized and used as the chain extender in the preparation of a silicone‐modified WPU dispersion. Both the formation of hybrid networks based on the condensation of trimethoxysilane groups and the enhanced microphase separation of the hard and soft segments have been found to rely on the strong hydrogen‐bonding capability of the urea‐containing spacers, which link the alkoxysilane groups with the backbone of WPU. Because of the synergism of chemically bonded silsesquioxane and physically hydrogen bonded hard domains serving as crosslinking points, the mechanical properties of the hybrid films of WPU are improved, especially the modulus and yield strength. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46628.     

Synthesis and characterization of UV-curable waterborne polyurethane acrylate possessing perfluorooctanoate side-chains

The dispersion of UV-curable waterborne polyurethane acrylate possessing perfluorooctanoate side-chains (FPUA) terminated with pentaerythritol triacrylate (PETA) was synthesized by incorporating fluorine groups into the side chains of the polyurethane macromolecular from condensation polymerization by using perfluorooctanoate glycerate (OF-diols) as chain extender, while the polyurethane macromolecular was synthesized from isophoronediisocyanate (IPDI), dimethylol propionic acid (DMPA), and poly (propylene glycol) (PPG) etc. The chain extender was prepared from 2,2-dimethyl-1,3-dioxolane-4-methyl perfluorooctanoate (OF-diols-pg) by acid hydrolysis with trifluoroacetic acid. The structure of FPUA was characterized by FTIR, NMR, elemental analysis, UV–vis and Mass spectra, and the properties of the synthesized FPUA emulsion were also discussed. The effect of fluorine content on the UV-curing dynamics was studied and the UV-curing speed decreased with increment in fluorine content. Contact angle measurements shown that the hydrophobic property of the surface greatly increased by incorporation of fluorine into the polyurethane chain. In addition, scanning electron spectroscopy (SEM) analysis was applied to characterize the morphology of the fracture surface of the UV-cured FPUA which became phase-mixed after annealing.     

负离子型聚氨酯离聚体水分散过程的相反转

用异佛尔酮二异氰酸酯、聚己二酸新戊二醇酯和二羟甲基丙酸（DMPA）合成了负离子型聚氨酯离聚体．研究了该类离聚体在水分散过程中的相反转变化,讨论了DMPA质量分数和水分散温度对相反转过程的影响。结果表明,DMPA质量分数增加或水分散温度提高,可使相反转所需的时间缩短,分散液粒子粒径变小,粒径分布更均匀,黏度增大。水分散温度的作用较DMPA更为明显。差示扫描量热分析表明,水分散过程破坏了亲水性硬链段的有序性。傅里叶变换红外光谱分析表明,聚氨酯水分散液用乙二胺扩链后．脲羰基的氢键化程度随DMPA质量分数的增加、水分散温度的提高而提高。     

Effects of the chain‐extender content on the structure and performance of poly(lactic acid)–poly(butylene succinate)–microcrystalline cellulose composites

Composites of poly(lactic acid) (PLA) with poly(butylene succinate) (PBS) and microcrystalline cellulose (MCC) as reinforcements of the polymer matrix were prepared by melt blending to improve the brittleness of PLA. As a reactive compatibilizer, a chain extender was used in an attempt to solve the composites’ interfacial problems and to improve their mechanical properties; Fourier transform infrared spectroscopy indicated that the chain extender functionally reacted with PLA, PBS, and MCC mainly through end carboxyls or end hydroxyls. Scanning electron microscopy indicated that the chain extender significantly improved the cohesive interfacial forces. Differential scanning calorimetry and X‐ray diffraction showed that the chain extender inhibited crystallization, and these effects were greater when its percentage was increased. The addition of chain extender improved the tensile and impact strength of the composites, and this improvement was proportional to the chain‐extender percentage. However, the elongation at break decreased when the chain‐extender percentage was over 0.5% because of mild crosslinking within the resin matrix. Rheology indicated that the complex viscosity and storage and loss moduli of the composites increased with increasing amount of chain extender; this indicated that the addition of chain extender improved the melt strength and processability of the composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44895.     

水性聚氨酯胶粘剂性能的影响因素探讨Ⅱ——结构因素的影响

探讨了结构因素包括离子基含量,硬段/软段的物质的量比,低聚物二醇的结构和分子质量,异氰酸酯结构,扩链剂类型和扩链程度,离子基的中和程度或离子对的性质以及溶剂量对水性聚氨酯(WPU)分散液性能和胶膜力学性能的影响。     

Anionomeric waterborne poly(urethane semicarbazide) dispersions and their adhesive properties

Aqueous polyurethane dispersions were prepared from isocyanate‐terminated ionic polyurethane prepolymers by chain extension with dihydrazides. These water‐borne dispersions had excellent adhesive properties and were used to bond leather and canvas. The base polymers were varied with respect to (1) the ionic content with the same chain extender and (2) the nature of the chain extender with the ionic content kept constant. Studies on the particle size and viscosity revealed that the ionic content had an influence on the aforementioned properties: the particle size decreased and the viscosity increased with increasing ionic content. The polarity of the films cast from the dispersions were determined with contact‐angle measurements: hydrophilic character was exhibited by all the compositions. X‐ray studies revealed that the increase in the ionic content led to increasing intensities of the diffraction peaks due to increased secondary forces of bonding. The tensile strength measurements showed that the films were highly elastomeric and had good mechanical strength, which varied with the composition. A shear strength and peel strength analysis of specimens obtained through the bonding of leather to leather, leather to canvas, and canvas to canvas revealed that the waterborne dispersions were excellent adhesives for bonding leather surfaces. Thus, a very efficient, ecofriendly waterborne dispersion of polyurethane that could find applications in bonding leather in the footwear industry was prepared successfully. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008