Effect of hydroxyl‐terminated poly(fluoroalkyl methacrylate) main‐chain length on the microphase separation of waterborne fluorinated polyurethane

Waterborne fluorinated polyurethanes (WFPUs) based on hydroxyl‐terminated poly(fluoroalkyl methacrylate)s (HTPFMAs) with different main‐chain lengths were synthesized. The structure of HTPFMA was characterized using ¹H NMR spectroscopy, measurements of hydroxyl values and gel permeation chromatography. The microstructures of WFPUs were investigated using Fourier transform infrared spectroscopy, which indicated that hydrogen bonding interactions in hard segments of WFPUs were enhanced by the introduction of HTPFMA and increased with increasing main‐chain length of HTPFMA. The results of X‐ray diffraction demonstrated that increasing the main‐chain length of HTPFMA resulted in an increase of crystallinity in hard segments. Differential scanning calorimetry revealed that the melting temperature of micro‐crystallites in hard segments and the microphase separation increased with an increase of HTPFMA main‐chain length. Dynamic mechanical analysis and scanning electron microscopy also confirmed that HTPFMA with longer main‐chain length can promote the extent of microphase separation of WFPUs between soft and hard domains. The mechanical properties of WFPUs were improved due to the increase of microphase separation with increasing HTPFMA main‐chain length. © 2018 Society of Chemical Industry     

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。     

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     

Synthesis and characterization of crosslinking waterborne fluorinated polyurethane‐acrylate with core‐shell structure

Crosslinking core‐shell emulsions of waterborne fluorinated polyurethane‐acrylate (WFPUA) were successfully synthesized using a solvent‐free method. The crosslinkers of diacetone acrylamide and adipic dihydrazide were introduced into the WFPUA emulsions. The physical properties of hybrid emulsions such as the average particle size, stability, and viscosity were characterized. The core‐shell of crosslinking WFPUA emulsion synthesized in this study was observed by transmission electron microscopy. Then, the results of Fourier transform infrared spectroscopy, atomic force microscopy, and X‐ray photoelectron spectroscopy indicated that the fluorinated monomer (FA) had been polymerized into the crosslinking waterborne polyurethane‐acrylate polymer, and the fluorinated groups have evident enrichment on the film‐air surface with the increase of FA content. At the same time, the thermal properties, water repellent/antifouling properties, and mechanical properties were measured. Moreover, the thermal properties and the elongation are raised but tensile stress and shore hardness are decreased with the increase of FA content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40970.     

硬段对聚酯型聚氨酯弹性体微相分离的影响

以聚己二酸-1,4-丁二醇酯二醇(PBA)、4,4′-二苯基甲烷二异氰酸酯(MDI)、乙二醇(EG)、1,4-丁二醇(BDO)和1,6-己二醇(HD)等为主要原料,采用预聚体法制备了一系列热塑性聚氨酯弹性体(TPU)。通过对TPU流变性能、结晶性能、硬度与力学性能的研究,考察了不同扩链剂及不同硬段含量对TPU体系内部微相分离的影响。结果表明,HD-TPU与BDO-TPU微相分离情况相当,均大于EGTPU,且HD-TPU具有较好的结晶性能、拉伸强度及断裂伸长率;随TPU体系硬段含量增加,硬度和拉伸强度增加,断裂伸长率减小,相分离发生越早越快,结晶熔融温度越高,但相分离程度并不高。     

软段对IPDI基透明聚氨酯弹性体微相结构与性能的影响

采用不同结构的软段、扩链剂l,4-丁二醇和异佛尔酮二异氰酸酯(IPDI)为主要原料合成了透明聚氨酯弹性体。研究了软段结构变化对聚氨酯弹性体的微相结构、力学性能、热稳定性及光学透明性的影响。结果表明,相对分子质量高的软段比相对分子质量低的软段更易结晶,耐低温性能更好;与聚氧四亚甲基二醇(PTMG)相比,聚酯型聚己二酸丁二醇酯二醇(PBAG)更易结晶。结晶尺寸在纳米级,材料的透明性可达85％以上。软段含量增加对软段区的结晶影响较小,但力学性能下降明显。混合多元醇的加入进一步提高了聚氨酯弹性体的微相分离程度,有利于软段结晶,在宏观上表现为拉伸强度和弹性模量明显增加。     

炭黑对聚氨酯泡沫塑料微相分离和力学性能的影响

利用红外光谱仪（IR）、动态热机械分析仪（DMA）和力学性能测试法研究了炭黑对聚氨酸泡沫塑料的微相分离和力学性能的影响，并与基体泡沫做了对照。结果表明：炭黑能加速聚氨酯泡沫的微相分离，明显地降低泡沫的力学性能；如果采用先用TDI浸渍炭黑，能很大程度上降低炭黑对泡沫力学性能的不良影响。     

Preparation of PVDF/poly(tetrafluoroethylene‐co‐vinyl alcohol) blend membranes with antifouling propensities via nonsolvent induced phase separation method

Poly(vinylidene fluoride) (PVDF) was blended with a new amphiphilic copolymer, poly(tetrafluoroethylene‐co‐vinyl alcohol) [poly(TFE‐VA)], via non‐solvent induced phase separation (NIPS) method to make membranes with superior antifouling properties. The effects of the VA/TFE segment ratio of the copolymer and the copolymer/PVDF blend ratio on the properties of the prepared membranes were studied. Membranes with similar water permeabilities, surface pore sizes, and rejection properties were prepared and used in bovine serum albumin (BSA) filtrations with the same initial water flux and almost the same operating pressure, to evaluate the sole effect of membrane material on fouling propensity. While the VA/TFE segment ratio strongly affected the membrane antifouling properties, the effects of the copolymer/PVDF blending ratio were not so drastic. Membrane surface hydrophilicity increased, and BSA adsorption and fouling decreased upon blending a small amount of amphiphilic copolymer with a high VA/TFE segment ratio with PVDF (copolymer/PVDF blending ratio 1:5). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43780.     

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.     

固化剂用量对苯甲基化木材制得的聚氨酯树脂微相分离的影响

以二价酸酯与乙酸丁酯混合溶剂为液化试剂,将苯甲基化木材溶液化,得到的木材溶液与三羟甲基丙烷与甲苯二异氰酸酯的预聚物反应制备聚氨酯树脂。利用FTIR、SEM、DTA、TG及DSC等测试手段,研究了固化剂用量对聚氨酯树脂的微观结构和热性能的影响。结果表明,由于木材结构的特殊性和复杂性,使木材溶液得到的聚氨酯树脂较传统的聚氨酯热稳定性提高,表现在其软段、硬段的初始分解温度比传统的聚氨酯分别提高了 4℃和 99℃;随着w(固化剂)由 23. 8%增大到 69 .9%,树脂的玻璃化转变温度提高,微相分离程度增大,并出现相转变;且相转变完成后,即w(固化剂) =69. 9%时,涂膜各项性能指标发生明显的改善,其铅笔硬度可达 4H,附着力≥1级。     

Preparation and performance of waterborne UV‐curable polyurethane containing long fluorinated side chains

Novel waterborne UV‐curable polyurethane containing long fluorinated side chains (WUVFPU) was prepared and the fluorinated component was incorporated by two novel fluorinated macromolecular diols (FDO) with different chain length as chain extender. FDO was synthesized via free radical polymerization of hexafluorobutyl methacrylate (HFBMA) using 1‐thioglycerol (TG) as chain transfer agent. Extremely low dosage of FDO incorporated could change the surface property significantly. The influence of both the content and chain length of FDO on the surface energy, surface composition and morphology were investigated by contact angle measurement, XPS and AFM. Surface energy significantly decreased at extremely low concentration of FDO. The hydrophobicity was enhanced with increasing both the content and the chain length of FDO. XPS and AFM results revealed the enhancing hydrophobicity was attributed to the enrichment of F atoms and rougher surface morphology. Gel content, pencil hardness, adhesion, and optical transmittance tests were employed to investigate the coating properties of the UV‐cured films. The preparation and investigation of WUVFPU might provide better understanding of the influence of fluorinated chain length on the properties of polyurethane for theory. Moreover, it might provide a facile and effective route to prepare polyurethane materials with low surface energy for engineering and industry. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44506.     

Thermoplastic polyurethane elastomers based on polycarbonate diols with different soft segment molecular weight and chemical structure: Mechanical and thermal properties

A series of thermoplastic polyurethane elastomers based on polycarbonate diol, 4,4′‐diphenylmethane diisocyanate and 1,4‐butanediol was synthesized in bulk by two‐step polymerization varying polycarbonate diol soft segment molecular weight and chemical structure, and also hard segment content, and their effects on the thermal and mechanical properties were investigated. Dynamic mechanical analysis termogravimetric analysis, differential scanning calorimetry, Fourier transform infrared‐attenuated total reflection spectroscopy and mechanical tests were employed to characterize the polyurethanes. Thermal and mechanical properties are discussed from the viewpoint of microphase domain separation of hard and soft segments. On one hand, an increase in soft segment length, and on the other hand an increase in the hard segment content, i.e., hard segment molecular weight, was accompanied by an increase in the microphase separation degree, hard domain order and crystallinity, and stiffness. In phase separated systems more developed reinforcing hard domain structure is observed. These hard segment structures, in addition to the elastic nature of soft segment, provide enough physical crosslink sites to have elastomeric behavior. POLYM. ENG. SCI., 2008. © 2007 Society of Plastics Engineers     

乙烯脲改性水性聚氨酯脲的制备与性能

采用一种新型的扩链剂乙烯脲(EU),在聚氨酯硬段引入具有刚性环状二取代脲基团,通过控制脲含量、交联度以及软段相对分子质量来制备一系列的EU改性水性聚氨酯脲(PUU-EU),并利用透射电镜(TEM)、广角X射线衍射(WAXD)、动态力学机械分析(DMA)、热失重分析(TGA)等测试方法,系统地研究PUU-EU微观结构与氢键化程度、微相分离、耐热性、力学强度的关系,并与1,4-丁二醇(BDO)扩链制备的水性聚氨酯(WPU)进行对比。结果表明,在一定范围内,PUU-EU随脲含量增加,其氢键化程度愈发完善,微相分离程度随之增加,力学强度逐步提高。     

Thermoplastic polyurethanes from renewable resources: effect of soft segment chemical structure and molecular weight on morphology and final properties

The effect of soft segment molecular weight and chemical structure on the morphology and final properties of segmented thermoplastic polyurethanes containing various hard segment contents has been investigated from the viewpoint of the degree of microphase separation. Vegetable oil‐based polyesters and corn sugar‐based chain extender have been used as renewable resources. The synthesis has been carried out in bulk without catalyst using a two‐step polymerization process. Physicochemical, thermal and mechanical properties, and also morphology, have been studied using Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, atomic force microscopy, X‐ray diffraction and mechanical testing. Chemical structure and molecular weight of polyols strongly affect the properties of the synthesized segmented thermoplastic polyurethanes. An increase in soft segment molecular weight leads to an increase of the degree of soft segment crystallinity and microphase separation, thus giving enhanced mechanical properties and higher thermal stability. Copyright © 2012 Society of Chemical Industry     

聚氨酯弹性体合成工艺研究

对聚氨酯(PUR)弹性体的合成工艺进行详细的研究,重点探讨了4种不同加料方式对PUR弹性体性能的影响。结果表明,将甲苯二异氰酸酯(TDI)溶液滴入已经脱水的聚醚溶液中,待反应完成后滴入扩链剂1,4-丁二醇(BDO)及将已脱水的聚醚溶液滴入TDI溶液中,待反应完成后再滴入扩链剂BDO这两种加料方式合成的PUR弹性体力学性能较好,玻璃化转变温度也较低,微相分离程度最完善。同时通过红外光谱表征了PUR弹性体的分子结构。     

微相分离促进剂对MDI型聚氨酯弹性体的耐热性能影响研究

在聚氨酯弹性体固化过程中添加微相分离促进剂,通过差示扫描量热分析（DSC）和动态力学性能测试（DMA）表明,微相分离促进剂的加入提高了4,4′-二苯基甲烷二异氰酸酯（MDI）弹性体的微相分离程度;通过不同温度下的热失重分析（TGA）和力学性能高温保持率对比分析表明,添加了微相分离促进剂的聚氨酯弹性体耐热性能得到了提高。     

聚醚型聚氨酯的氢键、微相分离及性能

用本体一步法合成了5种不同硬段含量(11.0％～46.9％)的二苯甲烷-4,4′-二异氰酸酯/环氧乙烷封端型聚环氧丙烷聚醚/乙二醇的聚醚型聚氨酯,并借助于IR,DSC,DMS和材料试验机等手段对该聚氨酯的氢键、微相分离及力学性能进行了表征。结果表明:随着硬段含量的增加,其>NH与微区中的>C=O的氢键化程度逐渐提高,软段微区中—O—的氢键化程度逐渐降低;微相分离程度逐渐提高;拉伸强度及硬度随之增加,扯断伸长率在硬段含量40％左右出现极大值。     

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。     

The effect of fluorinated side chain attached on hard segment on the phase separation and surface topography of polyurethanes

It has been well established that polyurethanes exhibit a two-phase micro-structure due to the thermodynamic incompatibility between the soft segments and hard segments. In this work, we reported the effect of fluorinated side chain attached on hard segment on the phase separation and surface topography of polyurethanes. Two sets of fluorinated polyurethanes, namely, poly(ether urethane)s and poly(carbonate urethane)s containing various amounts of chain extender of fluorinated side chains, were investigated by DSC, XPS, DMA, AFM and FTIR. It was found that the phase separation in both bulk and surface increases in fluorinated poly(carbonate urethane)s and the phase mixing increases in fluorinated poly(ether urethane)s, with increasing amounts of fluorinated side chain. The increased degree of hydrogen bonding between hard segments and soft segments was observed by FTIR for fluorinated poly(ether urethane), which is believed to result in the enhanced phase mixing, and the enhanced association of domains with long-range order (hydrogen bonding) between hard segments was evident for fluorinated poly(carbonate urethane)s, which may correspond to the enhanced phase separation. The result is new and provides direct connection between surface topography and bulk phase separation of polyurethanes.     

Preparation,surface wetting properties,and protein adsorption resistance of well‐defined amphiphilic fluorinated diblock copolymers

Novel well‐defined amphiphilic fluorinated diblock copolymers P(PEGMA‐co‐MMA)‐b‐PC₆SMA were synthesized successfully by RAFT polymerization and characterized by FTIR, ¹HNMR and GPC. For copolymer coatings, static contact angles, θ, with water (θ_water ≥ 109.5^°) and n‐hexadecane (θ_hexadecane ≥ 68.9^°) pointed to the simultaneous hydrophobic and lipophobic characteristics of the copolymer surfaces. Dynamic contact angle measurements indirectly demonstrated that copolymer films underwent surface reconstruction upon contact with water, which results in a surface with surface coverage of polar PEG units. Moreover, the distinct nanoscale microphase segregation structures were proved by atomic force microscopy (AFM) images. Finally, using bovine serum albumin (BSA–FITC) as the model protein, copolymers exhibited excellent protein adsorption resistance. It is believed that the combination of surface reorganization and nanometer‐scale microphase segregation structure endows the excellent protein resistance for amphiphilic fluorinated copolymers. These results provide deeper insight of the effect of surface reconstruction and microphase segregation on the protein adsorption behaviors, and these amphiphilic fluoropolymers can expect to have potential applications as antifouling coatings in the field of marine and biomedical. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41167.