Synthesis and properties of novel biodegradable polyurethanes containing fluorinated aliphatic side chains

This study used 5H–octafluoropentanoylfluoride and 2-amino-2-methyl-1,3-propanediol to synthesize a novel fluoro chain extender 2,2,3,3,4,4,5,5-octafluoro-N-(1,3-dihydroxy-2-methylpropan-2-yl) pentanamide (ODMP). Furthermore, 4,4′-diphenylmethane diisocyanate served as the hard segment, polycaprolactone diol (PCL) served as the soft segment, and ODMP served as the chain extender in the novel synthesized polyurethanes (ODMP/PUs). Gel permeation chromatography revealed that the molecular weight of the ODMP/PUs increased when the ODMP content was increased. ¹H and ¹⁹F nuclear magnetic resonance and Fourier transform infrared spectroscopy verified that the ODMP chain extenders were successfully synthesized and that the ODMP chain extenders were successfully incorporated into the backbone of the PUs. The interaction between the -NH (hydrogen bond) and CF₂ groups in the ODMP/PUs became stronger when the ODMP content was increased. Thermal analysis revealed that the initial decomposition temperature of the ODMP/PUs decreased and the second decomposition temperature increased when the polymers’ ODMP content was increased. Higher ODMP content also resulted in the ODMP/PUs’ higher glass transition and dynamic glass transition temperatures and lower ODMP maximum stress and Young’s modulus, causing a lower elongation at break. ODMP/PUs with higher ODMP content exhibited more protrusions and more rugged surfaces. The chemical resistance of the ODMP/PUs increased when the fluorine content was increased. Scanning electron microscopy revealed that ODMP/PUs with higher PCL content exhibited higher levels of hydrolytic degradation. Finally, in vitro erythrocyte tests revealed that increasing the ODMP chain extender content reduced the average number of erythrocytes adhering to the surface of the PUs.     

1，3-丁二醇对PCL／MDI体系聚氨酯弹性体力学性能的影响

首先以聚己内酯多元醇（PCL）、4,4’-二苯基甲烷二异氰酸酯（MDI）、液化MDI和MDI-50为原料合成聚氨酯（PU）预聚体,再用混合扩链剂制备聚氨酯弹性体。讨论了预聚体异氰酸酯基（NCO）含量、异氰酸酯类型、1,3-丁二醇（1,3-BDO）含量、聚酯软段相对分子质量对聚氨酯弹性体力学性能的影响。结果表明：提高预聚体NC0基含量可使弹性体的硬度、300％定伸应力、拉伸强度和撕裂强度明显提高,拉断伸长率和冲击弹性则下降;纯MDI弹性体综合力学性能最好,液化MDI次之,MDI-50最差;提高1,3-BDO含量可使弹性体的硬度、撕裂强度和冲击弹性明显下降;软段相对分子质量为1000的聚氨酯弹性体的硬度、300％定伸应力、拉伸强度和撕裂强度较高,软段相对分子质量为2000的聚氨酯弹性体的拉断伸长率和冲击弹性较高。     

Synthesis and characterization of biodegradable polyurethanes based on L‐cystine/cysteine and poly(ϵ‐caprolactone)

Tunable biodegradable polyurethanes (PUs) with favorable mechanical properties were synthesized from 1,6‐hexamelthylene diisocyanate (HDI) as the hard segment, poly(?‐caprolactone) (PCL) as the soft segment, and L ‐cystine ester as chain extender. The structure of PUs was confirmed by FTIR and ¹H‐NMR. The results of differential scanning calorimeter, thermogravimetric analysis, dynamic mechanical analysis, and tensile test revealed that the thermal and mechanical properties of PUs were strongly influenced by the molecular weight of soft segment PCL. In the presence of glutathione, the disulfide group cleaved into thiols, realizing the PUs degraded and the molecular weight decreased. For PU [550], it remained only 50% of the original M_w. Evaluation of cell viability demonstrated the nontoxicity of the PUs, which facilitated their potential in biomedical applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects on the structure and properties of membranes formed by blending polydimethylsiloxane polyurethane into different soft‐segment waterborne polyurethanes

Polydimethylsiloxane polyurethane (PDMS‐PU), which was synthesized from PDMS as the soft segment, was blended into a variety of ester‐ or ether‐based soft‐segment waterborne polyurethanes with different concentrations to investigate the crystallization, thermal, and physical properties of the membrane formations. According to X‐ray analysis, the ether‐based PUs, synthesized from soft segments of poly(propylene glycol) (PPG1000) or poly(ethylene glycol) (PEG2000), were found to have maximum crystallinity at a 5% blending ratio of PDMS‐PU, but the ester‐based PU, synthesized from soft segments of polycaprolactone (PCL1250), had decreased crystallinity at a 5% blending ratio. Differential scanning calorimetric analysis revealed that the T_g,s values of PUs were highest when the blending ratio of PDMS‐PU was 5%–10%, except for PU from PCL1250. Moreover, ether‐based PUs showed maximum T_m,h values, but the T_m,h of the ester‐based PU was greatly reduced when PU with PCL1250 was blended with PDMS‐PU. In addition, the PU from PEG2000 had the highest melting entropy. Mechanical property analysis showed that the stress of ether‐based PUs would be increased when PUs were blended with a small amount of PDMS‐PU and that the stress of PU from poly(tetramethylene glycol) (PTMG1000) increased to its greatest value (20–30 MPa). On the other hand, the ester‐based PU, from PCL1250 blended with PDMS‐PU, would have reduced stress. On the whole, the stress and strain of PU from PEG1000 had excellent balance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 210–221, 2006     

Biodegradable polyurethanes: novel effects of the fluorine-containing chain extender on the thermal,physical and water vapor permeation properties

This study synthesized a novel fluoro chain extender, namely 2,2,3,3,4,4,4-heptafluoro-butynic acid 2,2-bis-hydroxymethyl-butyl ester (HFBA), by using 2,2,3,3,4,4,4-heptafluorobutanoyl chloride and trimethylolpropane. Novel polyurethanes (PUs), namely HFBA/PUs, were subsequently synthesized by adopting a hard segment (4,4′-diphenylmethane diisocyanate, MDI), a soft segment (polycaprolactone diol, PCL), and the synthesized chain extender (HFBA). The results of proton nuclear magnetic resonance spectroscopy, fluorine-19 nuclear magnetic resonance, and Fourier transform infrared spectroscopy (FT-IR) demonstrated the successful synthesis of the HFBA chain extender. Gel permeation chromatography revealed that the molecular weight of the HFBA/PUs increased with the HFBA content. Through FR-IR and X-ray photoelectron spectroscopy, we observed a strong hydrogen bond interaction between the NH groups and CF₂ or CF₃ groups in the HFBA/PUs. This interaction increased with the HFBA content. Additionally, increasing the HFBA content increased the initial decomposition temperature, glass transition temperature, dynamic Tg (Tgd), tensile strength, and Young’s modulus of the HFBA/PUs. These results were because HFBA was a hard segment, which stimulated a stronger interaction between the NH groups and CF₂ or CF₃ groups in the PUs. By contrast, the HFBA/PUs had low elongation-at-break values. Atomic force microscopy revealed a higher number of bump-like protrusions and higher surface roughness levels among HFBA/PUs with higher HFBA content ratios. Finally, we coated the HFBA/PUs onto polyethylene terephthalate fabrics and discovered that the coated fabrics demonstrated high waterproofing and water vapor permeability levels.     

Synthesis and characterisation of novel flame retardant polyurethanes containing designed phosphorus units

In this study, 2-carboxyethyl(phenyl)phosphinic acid (CEPPA) and trimethylolpropane (TMP) are used to synthesise a novel flame retardant containing phosphorus units: 5-hydroxy-3-(2-hydroxyethyl)-3-methylpentyl-3-[2-carboxyethylphenylphosphine]propanoate (HMCPP). Then, 4,4′-diphenylmethane diisocyanate (MDI) is taken as a hard segment, with HMCPP and polycaprolactone diol (PCL) as soft segments, and 1,4-butanediol (BD) is used as a chain extender to prepare a novel polyurethane (HMCPP/PUs). The results of ¹H NMR and FT-IR reveal the successful synthesis of the HMCPP flame retardant. The gel permeation chromatography analysis demonstrates that an increase in the HMCPP content is accompanied by a decrease in the molecular weight of PU. The FT-IR analysis reveals the complete NCO group exhaustion of PU and HMCPP/PUs. The thermal analysis shows that the initial decomposition temperature of PU is higher than that of HMCPP/PUs by 19 °C. Both DMA and DSC analyses show that the Tg and the dynamic Tg of PU are higher than those of HMCPP/PU. Stress-strain tests indicate that the HMCPP content is increased, the maximum stress and Young’s modulus of HMCPP/PUs are decreased, and the elongation at break is increased. All of the HMCPP/PUs exhibit excellent flame retardancy, obtaining higher than 27.7 in limiting oxygen indices and a V-0 rating in the UL-94 test.     

Thermal and mechanical properties of fiber‐forming poly(urethane semicarbazide)s

Fiber‐forming poly(urethane semicarbazide)s were prepared with poly(butylene adipate)glycol as soft‐segment domains and hexamethylene diisocyanate/terephthalic dihydrazide as hard‐segment domains. The hard‐segment content was varied via variations in the polyol/isocyanate molar ratio, and the films were characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. The effect of the hard‐segment‐content variation on the properties was studied by differential scanning calorimetry, stress–strain analysis, and dynamic mechanical testing. Differential scanning calorimetry showed that the samples exhibited a very low level of hard/soft‐segment phase mixing. The stress–strain analyses revealed that the elongation at break decreased with an increase in the hard‐segment content and that the mechanical property depended on the overall crystallinity of the samples. Dynamic mechanical tests revealed a high glassy‐to‐rubbery state modulus and a high degree of phase separation between the hard and soft segments. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 86–93, 2002     

Nanoclay-tethered shape memory polyurethane nanocomposites

The study investigated shape memory properties of nanoclay-tethered polyurethane nanocomposites. Polyurethanes based on polycaprolactone (PCL) diol, methylene diisocyanate, and butane diol and their nanocomposites of reactive nanoclay were prepared by bulk polymerization in an internal mixer and the values of shape fixity and shape recovery stress were determined as function of clay content. The melting point of the crystalline soft segment was used as the transition temperature to actuate the shape memory actions. It was seen that clay particles exfoliated well in the polymer, decreased the crystallinity of the soft segment phase, and promoted phase mixing between the hard and soft segment phases. Nevertheless, the soft segment crystallinity was enough and in some cases increased due to stretching to exhibit excellent shape fixity and shape recovery ratio. A 20% increase in the magnitude of shape recovery stress was obtained with the addition of 1 wt% nanoclay. The room temperature tensile properties were seen to depend on the competing influence of reduced soft segment crystallinity and the clay content. However, the tensile modulus measured at temperatures above the melting point of the soft segment crystals showed continued increases with clay content.     

Effect of filler content on the structure‐property behavior of poly(ethylene oxide) based polyurethaneurea‐silica nanocomposites

Poly(ethylene oxide) (PEO) based polyurethaneurea‐silica nanocomposites were prepared by solution blending and characterized by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Differential Scanning Calorimetry and tensile testing. The colloidal silica nanoparticles with an average size of 50 nm were synthesized by modified Stöber method in isopropanol. Silica particles were incorporated into three cycloaliphatic polyurethaneurea (PUs) copolymers based on PEO oligomers with molecular weights of 2,000, 4,600, and 8,000 g/mol. Hard segment content of PUs was constant at 30% by weight. Silica content of the PU nanocomposites varied between 1 and 20% by weight. Soft segment (SS) glass transition and melting temperatures slightly increased with increasing filler content for all the copolymers. Degree of SS crystallinity first increased with 1% silica incorporation and subsequently decreased by further silica addition. Elastic modulus and tensile strengths of PU copolymers gradually increased with increasing amount of the silica filler. Elongation at break values gradually decreased in PEO‐2000 based PU copolymer with increasing silica content, whereas no significant change was observed in PUs based on PEO‐4600 and PEO‐8000. Enhancement in tensile properties of the materials was mainly attributed to the homogeneous distribution of silica filler in polymer matrices and strong polymer‐filler interactions. POLYM. ENG. SCI., 58:1097–1107, 2018. © 2017 Society of Plastics Engineers     

Block architecture influence on the structure and mechanical performance of drawn polyurethane elastomers

Some natural biopolymers such as spider silk exhibit superb mechanical properties, characterised by their great toughness. Synthetic polyurethane (PU) copolymers also endow great toughness but lack silk's stiffness and strength. The aim of this work was to elucidate the role of segment block architectural features that influence PU stiffness and strength after cold drawing. For this purpose PUs with varied soft segment character, crystalline versus rubbery, as well as with different hard segment chemistries, 4,4′‐diphenylmethane diisocyanate/1,4‐butanediol versus 1,6‐hexamethylene diisocyanate/1,4‐butanediol, were synthesised by a two‐step polymerisation method. We found that the architecture of both block segments has a dramatic influence on drawn PU mechanical performance, in which PUs with crystallisable soft segments and crystalline hard segments are shown to have a greater impact on developing stiffer and stronger materials. © 2013 Society of Chemical Industry     

Microstructure - cyclic deformation property relationships of biodegradable di-crystalline triblock copolymers

The synthesis, morphological characterization and cyclic deformation behaviour of a double crystalline triblock copolymer containing crystalline poly(l-lactide) (PLLA) or random copolymer of poly(l-lactide) and polycaprolactone (PCL) hard segment and a random copolymer of polycaprolactone and poly(trimethylene carbonate) (PTMC) soft segment are presented. The hard segment content was varied via the CL/LLA molar ratio to produce copolymer with distinct morphologies. Differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS) and atomic force microscopy (AFM) measurements confirmed the existence of a microphase-separated structure and the domain size was largely affected by the hard segment PCL content. Furthermore, combined measurements of WAXD and stress - strain curves revealed the molecular mechanism responsible for the superior strain recovery behaviour. It was formed that the permanent set can be largely reduced by incorporating PCL into PLLA hard segment and the strain recovery is enhanced by the ease of PCL crystal rotation upon retraction.     

聚已内酯/聚氨酯共聚热致形状记忆材料的合成与表征

以聚己内酯（PCL）为软段,甲苯2,4-二异氰酸酯（TDI）为硬段,通过预聚合和扩链反应制得含结晶软段的聚氨酯形状记忆材料（SMPU）,通过差热分析、红外分析及X射线衍射对其微结构进行了表征。结果表明,随着硬段含量的增加,SMPU的结晶熔融温度上升,结晶度下降,形状回复率减小,形状固定率始终保持在98 %左右;随着PCL相对分子质量的提高,SMPU的结晶熔融温度减小,结晶度增大,回复响应温度逐渐降低。     

Structure‐property relationships of degradable polyurethane elastomers containing an amino acid‐based chain extender

A series of degradable polyurethanes of variable soft segment chemistry and content were synthesized and characterized. An amino acid‐based diester chain extender was used to confer degradability and both polycaprolactone diol (PCL) and polyethylene oxide (PEO) were used as soft segments. In addition, the diisocyanate component was a potentially nontoxic diisocyanate (2,6‐diisocyanato methyl caproate, LDI). The physicochemical properties of these unique series of polyurethanes were investigated. It was found that the PEO containing polyurethanes were generally weak, tacky amorphous materials. In contrast, the PCL polyurethanes were relatively strong, elastomeric materials which ranged from completely amorphous to semicrystalline as noted by differential scanning calorimetry. The PCL containing polyurethanes exhibited increasing tensile strength, modulus, and ultimate strain with increasing PCL molecular weight because of increasing phase separation and increasing soft segment crystallinity. Fourier transform infrared analysis showed significant hard segment urea and urethane hydrogen bonding which increased with hard segment content, although interphase bonding is believed to be significant for the PCL polyurethanes. Surface characterization carried out by contact angle analysis and X‐ray photoelectron spectroscopy indicated soft segment surface enrichment for all of the polyurethanes. The PEO‐based polymers were very hydrophilic whereas the PCL‐based polymers displayed significantly higher contact angles, indicating greater surface hydrophobicity. The observed diversity in material properties suggests that these polyurethanes may be useful for a wide range of applications. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1522–1534, 2000     

The temperature-sensitive water vapor permeation control of polyurethane membrane using the graft-polymerized poly(N-isopropylacrylamide) and the impact on the tensile strength and shape recovery effect

Poly(N-isopropylacrylamide) (poly(NIPAM)) was grafted onto polyurethane (PU) using a graft-polymerization method to develop a thermo-responsive PU and to investigate the impact on cross-link density, solution viscosity, soft segment thermal transitions, tensile properties, shape memory effect, and water vapor permeation through PU membrane. The soft segment crystallization peak sharply decreased with the increase in NIPAM content, whereas the glass transition temperature (T_g) slightly increased with the increase of NIPAM content. The breaking tensile stress rapidly increased with the increase in NIPAM content due to the cross-linking effect between the grafted poly(NIPAM) chains, whereas the strain at break did not significantly decreased as the NIPAM content increased. The shape recovery at 10°C rapidly increased from 46.9% for plain PU to above 90% after the grafting of poly(NIPAM) onto PU, and the shape retention at ?25°C slightly decreased with the increase in NIPAM content. Finally, the grafting of poly(NIPAM) onto PU demonstrated the temperature-responsive control of water vapor permeation through PU film due to the conformational change of the grafted poly(NIPAM) with the increase of temperature and the potential applications of the resulting PUs are discussed.     

Preparation and characterization of biodegradable polyurethanes composites filled with silver nanoparticles-decorated graphene

In this study, polyurethane (PU) was synthesized using 4,4,-diphenylmethane diisocyanate (MDI) as a hard segment, polycaprolactone diol (PCL) as the soft segments and 1,4-butandiol (1,4-BD) as a chain extender. Nanosilver/graphene (Ag/G) was added to the PU matrix to prepare Ag/G/PU nanocomposites. EDS, SEM and XRD are used for assaying the silver content and characterization of Ag/G. TEM, FT-IR, XRD and EDS were used to characterize the structure and morphology of the Ag/G/PUs nanocomposites. The TEM results show that Ag/G belongs to sheet structures and is dispersed in a PU matrix. The SEM showed that the strong interfacial adhesion between the Ag/G and PU is indicated. FT-IR spectra analysis shows that the functional group of PU is free of obvious changes by adding a small amount of Ag/G in the PU matrix. XRD results showed that the main crystalline peak (26°) of Ag/G became more apparent with increasing content of Ag/G, and EDS showed that the content of Ag increased with increasing content of Ag/G in the Ag/G/PUs nanocomposites. The thermal stability and mechanical properties of Ag/G/PUs nanocomposites are improved with increasing content of Ag/G. Contact angle and AFM results showed that the hydrophobicity and surface roughness increased with increasing content of Ag/G. Moreover, the Ag/G/PUs nanocomposites exhibit antibacterial activities toward Staphylococcus aureus as well as Escherichia coli and their antibacterial rates increase with increasing Ag/G. In addition, the electrical conductivity measurements showed that both surface and volume resistance of the Ag/G/PUs nanocomposites decreased as the amount of Ag/G increased.     

In vitro degradation of poly(l-lactide)/poly(ε-caprolactone) blend reinforced with MWCNTs

The physical and mechanical properties of poly(l-lactide)/poly(??-caprolactone) (PLLA/PCL) blends reinforced with multiwalled carbon nanotubes (MWCNTs) before and after in vitro degradation were investigated. Because of brittleness, PLLA needs to be plasticized by PCL as a soft polymer. The MWCNTs are used to balance the stiffness and the flexibility of PLLA/PCL blends. The results showed that with incremental increase in concentration of MWCNTs in composites, the agglomerate points of MWCNTs were increased. The physical and mechanical properties of prepared PLLA/PCL blends and MWCNT/PLLA/PCL nanocomposites were characterized. The X-ray diffraction analysis of the prepared blends and composites showed that MWCNTs, as heterogeneous nucleation points, increased the lamella size and therefore the crystallinity of PLLA/PCL. The mechanical strength of blends was decreased with incremental increase in PCL weight ratio. The mechanical behavior of composites showed large strain after yielding and high elastic strain characteristics. The tensile tests results showed that the tensile modulus and tensile strength are significantly increased with increasing the concentration of MWCNTs in composites, while, the elongation-at-break was decreased. The in vitro degradation rate of polymer blends in phosphate buffer solution (PBS) increased with higher weight ratio of PCL in the blend. The in vitro degradation rate of nanocomposites in PBS increased about 65% when the concentration of MWCNTs increased up to 3% (by weight). The results showed that the degradation kinetics of nanocomposites for scaffolds can be engineered by varying the contents of MWCNTs.     

Thermophysical and mechanical properties of novel polymers prepared by the cationic copolymerization of fish oils, styrene and divinylbenzene

New polymeric materials have been prepared from the cationic copolymerization of fish oil ethyl ester (NFO), conjugated fish oil ethyl ester (CFO) or triglyceride fish oil (TFO) with styrene and divinylbenzene initiated by boron trifluoride diethyl etherate (BF₃·OEt₂). These materials are typical thermosetting polymers with crosslink densities ranging from 1.1×10² to 2.5×10³ mol/m³. The thermogravimetric analysis of the new fish oil polymers exhibits three distinct decomposition stages at 200–340, 340–500 and >500°C, respectively, with the maximum weight loss rate at approximately 450°C. Single glass-transition temperatures of T_g=30–109°C have been obtained for the fish oil polymers. As expected, these new polymeric materials exhibit tensile stress–strain behavior ranging from soft rubbers through ductile to relatively brittle plastics. The Young's modulus (E) of these materials varies from 2 to 870 MPa, the ultimate tensile strength (σ_b) varies from 0.4 to 42.6 MPa, and the percent elongation at break (ε_b) varies from 2 to 160%. The failure topography indicates typical fracture mechanisms of rigid thermosets, and the unique fibrillation on the fracture surface gives rise to relatively high mechanical properties for the corresponding NFO polymer. The new fish oil polymers not only exhibit thermophysical and mechanical properties comparable to petroleum-based rubbery materials and conventional plastics, but also possess more valuable properties, such as good damping and shape memory behavior, which most petroleum-based polymers do not possess, suggesting numerous, more promising applications of these novel fish oil-based polymeric materials.     

Structure–property relationships of polycarbonate diol‐based polyurethanes as a function of soft segment content and molar mass

Segmented thermoplastic polyurethanes (PUs) have been synthesized with polycarbonate diol as soft segment and 4,4′‐diphenylmethane diisocyanate and butanediol as hard segment. Two different series employing two different soft‐segment molar mass, 1000 and 2000 g/mol, and by changing the hard‐segment content from 32 to 67% have been investigated with the aim to elucidate the effect of the different content variations on the properties. Morphological, thermal, and mechanical properties have been studied by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), wide angle X‐ray diffraction, atomic force microscopy, tensile and tear strength, hardness, and specific gravity tests. Properties have been explained from the standpoint of miscibility between hard‐ and soft‐segment microdomains of the tailored segmented PUs through an exhaustive analysis. FTIR, DSC, and DMA measurements revealed that miscibility between hard and soft microdomains increases as the molar mass of the macrodiol decreases. An increase in hard‐segment content entailed the formation of larger hard domains with higher crystallinity what results in superior mechanical properties such as higher tensile stress and tear strength, and hardness. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41704.     

Study on the liquefied‐MDI‐based shape memory polyurethanes

A series of liquefied‐MDI‐based polyurethanes having shape memory behavior, with various soft segments, chain extenders, and micro‐phase separation promoters were synthesized. Their morphology and properties were investigated in terms of thermal properties, dynamic mechanical properties, and shape recovery behavior. The results indicate that the soft segment formed with longer chain segment incline to crystallize during the cooling scans and the resulting SMPU have the higher crystallinity. Meanwhile, the chain extenders, which can enhance the polarity of hard segment, incline to have excellent shape memory properties with bigger storage modulus in rubbery state too. It was also found that the micro‐phase separation promoters have great influence on the shape memory behavior due to the enhancement of micro‐phase separation of SMPU. Furthermore, it was proved again that SMPU with longer soft segment and lower hard segment contents usually showed good shape memory behavior. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

1,3-丁二醇对PTMG/MDI体系聚氨酯弹性体力学性能的影响

以纯4,4′-二苯基甲烷二异氰酸酯（MDI）MDI-100、液化MDI（C-MDI）、MDI-50和四氢呋喃均聚醚（PTMG）为原料合成聚氨酯（PU）预聚体,再分别与KD和KC扩链剂制备PU弹性体。研究了1,3-BDO含量、异氰酸酯类型、预聚体NCO基含量、聚醚软段相对分子质量对PU弹性体力学性能的影响。结果表明,提高1,3-BDO含量可使PU弹性体的硬度、撕裂强度和冲击弹性明显下降;纯MDI弹性体综合力学性能最好,液化MDI次之,MDI-50最差;提高预聚体NCO基含量可使弹性体的硬度、300%定伸应力和撕裂强度明显提高,拉断伸长率和冲击弹性则下降;软段相对分子质量为1000时,PU弹性体的300%定伸应力、拉伸强度和撕裂强度均增加;软段相对分子质量为1800以上,拉断伸长率和冲击弹性增加。