Preparation and properties of segmented thermoplastic polyurethane elastomers with two different soft segments

Thermoplastic polyurethane elastomers were prepared from 4,4‐diphenylmethane diisocyanate (MDI)/1,4‐butanediol (BD)/poly(propylene glycol) (PPG) and MDI/BD/poly(oxytetramethylene glycol) (PTMG). The MDI/BD‐based hard‐segment content of polyurethane prepared in this study was of 39–65 wt %. These polyurethane elastomers had a constant soft‐segment molecular weight (M_n , 2000), but a variable hard‐segment block length (n, 3.0–10.1; M_n , 1020–3434). The effects of the hard‐segment content on the thermal properties and elastic behavior were investigated. These properties of the PPG‐based MPP samples and the PTMG‐based MPT samples were compared. The polyurethane prepared in this study had a hard‐segment crystalline melting temperature in the range of 185.5–236.5°C. With increasing hard‐segment content, the dynamic storage modulus and glass transition temperature increased in both the MPP and MPT samples. The permanent set (%) increased with increasing hard‐segment content and successive maximum elongation. The permanent set (%) of the MPP samples was higher than that of MPT samples at the same hard‐segment content. The value of K (area of the hydrogen‐bonded carbonyl group/area of the free carbonyl group) increased with increasing hard‐segment content in both the MPP and MPT samples, and the K value of the MPT samples was higher than that of the MPP samples at the same hard‐segment content. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 345–352, 1999     

Synthesis,characterisation, and chemical degradation of segmented polyurethanes with butylamine for chemical recycling

Polyurethane elastomers (PU) have been synthesized from polytetramethylene glycol 2000 (PTMG 2000); 4, 4′‐diphenylmethane diisocyanate (MDI) and 1, 4‐butanediol (BD) as chain extender. This synthesis has been done in two steps known as prepolymer methods. The concentration of soft segments and hydrogen attachment in the matrices, have been studied. The results show that the glass transition of the soft segment T_g(s) do not take any changes with the concentration of the soft segment in the matrices. Although, the glass transition temperature of the hard segment T_g(H) increases when the concentration of the hard segment increases in the matrices. In general, the properties of the polyurethane elastomers depend on the extenders nature, the synthesis methods, phase segregation etc. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of prepolymer structure on the electro-optic performance of polymer dispersed liquid crystals

The effect of prepolymer structure on the electro-optic properties of polymer dispersed liquid crystals (PDLCs) prepared from UV-cured polyurethane acrylates (PUAs) has been studied. Among four types of films with different soft-segment structure, polypropylene glycol (PPG)- and polytetramethyl ether glycol (PTMG)-based PUAs gave lower threshold (V₁₀) and operating (V₉₀) voltages, whereas polycaprolactone diol (PCL)-based PUAs gave higher V₁₀ and V₉₀ voltages. The use of mixed polyol polypropylene glycol/ poly(tetramethylene adipate)diol) (PPG/PTAd) gave an electro-optic response intermediate between the two. Regarding the effect of hard segment type, that from a linear aliphatic diisocyanate (hexamethylene diisocyanate, HDI) gave the lowest V₁₀ and V₉₀ voltages as well as transparent–translucent transition temperature compared with those from cycloaliphatic diisocyanates. This was interpreted in terms of a more flexible nature and hence a lower glass transition temperature of HDI-based PUA. © 1998 SCI.     

软段结构对脂肪族聚氨酯弹性体的结构与性能影响

分别采用聚丙二醇(PPG)、聚四氢呋喃二元醇(PTMG)、聚己二酸一缩二乙二醇三羟甲基丙烷酯多元醇(726)和聚己二酸新戊二醇酯二元醇(756)4种不同软段制备了基于异佛二酮二异氰酸酯(IPDI)的脂肪族聚氨酯弹性体(PUE),并通过FT-IR、DSC和TGA等表征了软段结构对PUE结构与性能的影响。结果表明,在相同硬段含量的条件下,PTMG制备的PUE具有最高的交联密度和最低的氨酯羰基氢键化程度。聚酯型PUE的耐热性和热氧老化性能均优于聚醚型PUE,由756合成的PUE具有最好的老化性能和热稳定性。     

Microphase-separated structure and mechanical properties of norbornane diisocyanate-based polyurethanes

Norbornane diisocyanate (NBDI: 2,5(2,6)-bis(isocyanatomethyl)bicyclo[2.2.1]heptane) is a new commercialized diisocyanate. NBDI-based polyurethane elastomers (PUEs) were prepared from poly(oxytetramethylene) glycol (PTMG), NBDI and 1,4-butanediol (BD) by a prepolymer method. Microphase-separated structure and mechanical properties of the NBDI-based PUEs were compared with general aliphatic and cycloaliphatic diisocyanate-based PUEs. The diisocyanates used were isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (HMDI) and 1,6-hexamethylene diisocyanate (HDI). Regular polyurethanes were also prepared as hard segment models from each isocyanate and BD to understand the feature of each hard segment chain. The HDI-based PUE showed the largest Young's modulus and tensile strength in the four PUEs due to the ability of crystallization of the hard segment component and the strongest microphase separation. HMDI has both properties of aliphatic and cycloaliphatic diisocyanates because of its high symmetrical chemical structure compared with NBDI and IPDI. On the other hand, the NBDI- and IPDI-based PUEs have an inclination to phase mixing, leading to decreased Young's modulus and tensile strength. The NBDI-based PUE exhibited better thermal properties at high temperatures due to stiff structure of NBDI.     

Polyurethane elastomers based on molecular weight advanced poly(ethylene ether carbonate) polyols. IV. Effects of poly(propylene glycol) modified diols

A series of polyurethane elastomers with a (A{BC}_m)n type of structure have been prepared and characterized based on poly(propylene glycol) modified poly(ethylene ether carbonate) polyols, where the poly(propylene glycol) content and block length were varied systematically. Strength and modulus properties showed a marked dependence on modifier level and exhibited synergistic property improvements at 25–50 wt % modifier, relative to both unmodified poly(ethylene ether carbonate) diol and poly(propylene glycol) controls. DMA results indicated an increased modulus for the modified plaques throughout the rubbery plateau region, with higher thermal dissociation temperatures. Excellent organic solvent resistance was maintained with 25–50 wt % poly(propylene glycol) modification in the soft segment. Chemical structure of the polyurethane elastomers was established by proton and ¹³C-NMR spectroscopy. The morphology of these modified polyurethanes appears to be quite complex. Since the modified soft segments are block copolymers of blocks with a tendency toward immiscibility, some microphase separation within the soft segment domains of the polyurethane polymers might be expected. The soft segment T_g is highest where properties are maximized, suggesting changes in phase mixing. © 1992 John Wiley & Sons, Inc.     

透明聚氨酯胶粘剂的合成与性能研究

用异佛尔酮二异氰酸酯（IPDI）,聚氧四亚甲基二醇（PTMG－1000）,1,4－丁二醇（1,4－BD0合成了透明聚氨醋（PU）胶粘剂,并对该胶粘剂进行了红外光谱,热性能以及力学性能的测试,结果表明：CNO／OH摩尔比略大于1,适当的1,4－BD与PTMG比例能获得力学,光学性能优良的PU胶粘剂。不同的原料配比对聚氨酯分子链中的段与软段的比例,硬段区的有序性有较大的影响。     

Emulsion of polyurethane having thermosetting properties. II. Relation between the mechanical properties of film and the polyurethane structure

A self-emulsifiable polyurethane emulsion having thermosetting property was prepared by the following procedure: the polyurethane–urea–amine was first prepared by the reaction of diethylene–triamine with a prepolymer containing terminal isocyanate groups in a ketone solvent, and then the primary amino group in the polyurethane–urea–amine was reacted with epichlorohydrin. The mixture was neutralized with an aqueous acid, and finally the ketone solvent was removed by distillation in vacuo. In the polyurethane, polytetramethylene glycol (PTMG) was the base polymer functioning as the soft segment. The present paper reports the effects of the following variables on the mechanical properties of the film prepared from the polyurethane emulsion, i.e., the M _n of PTMG, the molar ratio of diethylene–triamine (DTA) to prepolymer containing terminal isocyanate groups, the structure of the isocyanate end group and the molar ratio of tolylene diisocyanate (TDI) with PTMG. The best elastomer property was realized when M_n of PTMG was 2000, TDI/PTMG molar ratio was 2.0, and prepolymer/DTA molar ratio was 0.85.     

TODI类浇注型聚氨酯弹性体的耐热性能研究

用3,3'-二甲基-4,4'-联苯二异氰酸酯(TODI)与聚四氢呋喃(PTMG)、聚己内酯多元醇(PCL)合成了一系列浇注型聚氨酯弹性体,考察了不同聚合物多元醇、扩链剂以及硬段含量对弹性体耐热性能和力学性能的影响.结果表明:PCL体系的耐热性能和力学性能优于PTMG体系,其拉伸强度在120℃下保有率>90%;用3,3'...     

Relationship between structure and dynamic mechanical properties of thermoplastic polyurethane elastomer containing bi-soft segment

In this work, we investigated the microphase separation, mechanical, and dynamic mechanical properties of thermoplastic polyurethane elastomers (TPUs) with one-soft segment (polypropylene glycol, PPG, or hydroxyl-terminated polybutadiene, HTPB) or bi-soft segment (PPG and HTPB) using FTIR, XRD, SAXS and amplitude modulated-frequency modulated viscoelastic mode of AFM (AM-FM mode AFM) methods. The results showed that the microphase separation process of hard and soft segments (HS and SS) in TPU containing PPG and HTPB soft segments (PPG-HTPB-PU) was restricted by randomly alternated bi-soft segments, which results in formation of a low content of irregular-shaped hard domain (HD). In addition, the microphase separation of PPG-HTPB-PU induced a triple-phased structure of HD, HTPB rich phase and mesophase. The mesophase of PPG-HTPB-PU was formed of HS, PPG and HTPB segments which were excluded out of HD and HPTB rich domains during microphase separation process. The damping temperature range (at tan δ greater than 0.3) of PPG-HTPB-PU was from −14.6 to 32.1°C (46.5°C) which was more broad than that of TPU containing HTPB soft segment (HTPB-PU). The broad damping temperature range of PPG-HTPB-PU is mainly attributed to the enhanced energy consumption caused by the frictional motions of mixed segments of mesophase.     

不同聚醚二元醇软段对光固化水性聚氨酯乳液性能的影响

以不同聚醚二元醇、异佛尔酮二异氰酸酯、2,2-双羟甲基丙酸、甲基丙烯酸-2-羟基乙酯为主要原料,通过丙酮法合成光固化水性聚氨酯(WPU)乳液,讨论了不同聚醚软段对光固化WPU乳液性能的影响.结果表明,由聚四氢呋喃醚二元醇PTMG1000和PTMG2000制备的光固化WPU乳液具有较小的粒径和粘度,其交联后的膜具有较高储...     

Synthesis and characterization of poly[(butylene succinate)‐co‐(butylene terephthalate)]‐b‐poly(tetramethylene glycol) segmented block copolymer

Polyester‐polyether segmented block copolymers of poly[(butylene succinate)‐co‐poly(butylene terephthalate)] (PBS–PBT) and poly(tetramethylene glycol) (PTMG) (M_n = 2000) with various compositions were synthesized. PBT content in the PBS was adjusted to ca. 5 mol %. Their thermal and mechanical properties were investigated. In the case of copolymer, the melting point of the PBS–PBT control was 107.8°C, and the melting point of the copolymer containing 70 wt % of PTMG was 70.1°C. Crystallinity of soft segment was 5 ∼ 17%, and that of hard segment was 42 ∼ 59%. The breaking stress of the PBS–PTMG control was 47 MPa but it decreased with increasing PTMG content. In the case of copolymer containing 70 wt % of PTMG, breaking stress was 36 MPa. Contrary to the decreasing breaking stress, breaking strain increased from 300% for PBS–PBT control to 900% for a copolymer containing 70 wt % of PTMG. The shape recovery ratios of the copolymer containing 70 wt % PTMG were almost twice of those of copolymers containing 40 wt % PTMG. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2067–2075, 2001     

Soft segmental effect of methylene bis(p‐cyclohexyl isocyanate) based thermoplastic polyurethane impregnated with lithium perchlorate/propylene carbonate on ionic conductivity

Thermoplastic polyurethane (TPU) was employed as the polymer matrix for ion conduction as gelled electrolytes with lithium perchlorate (LiClO₄) in propylene carbonate (PC) solution. The TPU was prepared by methylene bis(p‐cyclohexyl isocyanate) as the hard segment while employing both poly(ethylene glycol) (PEG) and poly(tetramethylene glycol) (PTMG) as the soft segments. The copolymer comprising both PEG and PTMG was prepared such that it possessed the combined characteristics of good conductivity from the former and good mechanical properties from the latter. All the polymers were characterized by gel permeation chromatography, differential scanning calorimetry, and Fourier transform IR spectroscopy. The conductivity data were obtained from alternating current impedance experiments. The results revealed that the copolymer containing both PEG and PTMG as the soft segments showed better performance than TPU containing either PEG or PTMG. The copolymer TPU(PEG/PTMG) proved to be a good gelled electrolyte from 5 to 85°C. This copolymer, impregnated with 150% LiClO₄/PC, possessed good mechanical strength and conductivity as high as 10^?3 S/cm. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 935–942, 2001     

Thermoplastic polyurethanes with isosorbide chain extender

Isosorbide, a renewable diol derived from starch, was used alone or in combination with butane diol (BD) as the chain extender in two series of thermoplastic polyurethanes (TPU) with 50 and 70% polytetramethylene ether glycol (PTMEG) soft segment concentration (SSC), respectively. In the synthesized TPUs, the hard segment composition was systematically varied in both series following BD/isosorbide molar ratios of 100 : 0; 75 : 25; 50 : 50; 25 : 75, and 0 : 100 to examine in detail the effect of chain extenders on properties of segmented polyurethane elastomers with different morphologies. We found that polyurethanes with 50% SSC were hard elastomers with Shore D hardness of around 50, which is consistent with assumed co‐continuous morphology. Polymers with 70% SSC displayed lower Shore A hardness of 74–79 (Shore D around 25) as a result of globular hard domains dispersed in the soft matrix. Insertion of isosorbide increased rigidity, melting point and glass transition temperature of hard segments and tensile strength of elastomers with 50% SSC. These effects were weaker or non‐existent in 70% SSC series due to the short hard segments and low content of isosorbide. We also found that the thermal stability was lowered by increasing isosorbide content in both series. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42830.     

E-300扩链聚氨酯弹性体的力学性能研究

以多元醇(PEA，PPG，PTMG)，PDI，E-300为原料，制备了PU弹性体。研究了多元醇类型，NCO基含量，扩链剂用量和硫化时间等因素对PU弹性体力学性能的影响。结果表明：拉伸强度、拉断伸长率和冲击弹性最高的分别是PEA-PU，PPG-PU和PTMG-PU；PU的硬度、强度和模量随预聚体NCO基含量增加而增加；扩链剂的用量为90％时，PU的力学性能最佳。     

Alkali reduction and reactive dye dyeing of T/N nonwoven fabrics dipped into silicon‐containing,water‐borne polyurethane

Two series of anionic water‐borne polyurethanes with alkali resistance and covalent bonds of a reactive dye were synthesized with different molar ratios of poly(tetramethylene glycol) (PTMG). They were classified with respect to PTMG 1000 and PTMG 2000. The fiber blends of polyester/nylon nonwoven fabrics were dipped into silicon‐containing, water‐borne polyurethane and squeezed to an 80% pickup ratio. Finally, the manmade leather was treated with alkali reduction and dyed with a reactive dye. The alkali reduction and the thermal, mechanical, and dyeing properties of the manmade leather were studied. For alkali reduction, different ratios of NaOH and Na₂CO₃ concentrations were used. Na₂CO₃ was used because of its better spreading and buffering properties. The softness and breaking load were measured and related to the weight reduction. For the dyeing properties, a reactive dye with vinyl sulfone groups was found to bond with the OH group of water‐borne polyurethane by covalent bonding. On the basis of alkali reduction, a mixture of NaOH and Na₂CO₃ with a concentration ratio of 0.1N/0.2N could lead to better softness and alkali reduction of leather. For the mechanical properties, leather of the PTMG 1000 series showed a higher breaking load than leather of the PTMG 2000 series. However, less elongation in the PTMG 1000 series resulted. Differential scanning calorimetry showed an endothermic peak at 50–100°C. This indicated that the glass‐transition temperature of the hard segment decreased with an increasing amount of the soft segment in leather; meanwhile, both the glass‐transition temperature of the soft segment and the melting temperature of the hard segment also decreased as the content of the soft segment increased. For the dyeing properties, the reactive blue dye could reach up to 96.1% dye uptake in the polyurethane part of the leather. Moreover, the washing fastness could be graded as high as 4–5, and the light resistance was also graded to 4–5, in the dyed leather. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2324–2335, 2005     

Structural characterization and mass transfer properties of polyurethane block copolymer: influence of mixed soft segment block and crystal melting temperature

An attempt has been made to investigate the influence of mixed soft segment on structure and mass transfer properties of segmented polyurethane (SPU). For this purpose polyurethane block copolymer containing soft segment such as polycaprolactone glycol (number‐average molecular weight 3000, PCL 3000), PCL 3000–polypropylene glycol (number‐average molecular weight 3000, PPG 3000), PCL 3000–polytetramethylene glycol (number‐average molecular weight 2900, PTMG 2900), PPG 3000–PTMG 2900, were synthesized using a two‐step or three‐step synthesis process. All the SPUs were modified with the hydrophilic segment, i.e. diol‐terminated poly(ethylene oxide) (number‐average molecular weight 3400, PEG 3400). Fourier‐transform infrared, wide‐angle X‐ray diffraction, differential scanning calorimetry, and dynamic mechanical thermal analysis were used to characterize the polyurethanes. The mass transfer properties were measured by equilibrium sorption and water vapor permeability measurements. Mixed blocks loosen the inter‐chain interaction due to phase mixing which decreases the crystallization of the soft segment in the resulting SPU. The crystallinity of mixed polyol block SPU increases when both polyols are crystallizable in the pure state. Highest loss tan δ value was observed for the sample containing PTMG 2900–PPG 3000 mixed soft segment due to their flexible and phase mixed structure which increases the chain mobility; this sample performed best among all four SPUs in equilibrium water sorption as well as water vapor permeability owing to their loose and nearly amorphous structure. Soft segment crystal melting further enhances the water vapor permeability significantly, which would make the membrane suitable for breathable textiles, packaging and medical applications. Copyright © 2006 Society of Chemical Industry     

Characteristics of PPG-based thermoplastic polyurethane doped with lithium perchlorate

Segmented thermoplastic polyurethane (TPU) was synthesized from methylene bis(cyclohexyl isocyanate) (H₁₂MDI), ethylenediamine (EDA), and poly(propylene glycol) (PPG) with a molecular weight of 1000. The ratio of hard segment to soft segment (NCO/OH) is changed to test the chemical and physical properties. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and impedance spectroscopy (IS) were utilized to monitor the phase change of these TPU samples with various lithium perchlorate (LiClO₄) concentrations. Significant changes occur in the FTIR spectrum of the TPU with LiClO₄ concentration above 0.5 mmol/g TPU, indicating that an interaction existed between the lithium cation and the hard segment or soft phase. The soft-segment T_g increased with increasing LiClO₄ concentration through the examination of DSC. IS results indicate an increase in bulk conductivity as the salt concentration is increased. Electrochemical stability of the TPU sample was studied by cyclic votammetry (CV). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 389–399, 2001     

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     

Morphology of polyurethane–isocyanurate elastomers

The dynamic viscoelastic properties and thermal transition behavior of reaction injection molding (RIM) and cast polyurethane—isocyanurate elastomers have been studied as a function of various segments (soft and hard urethane, and hard isocyanurate) content. RIM and cast elastomers were prepared at different concentrations of soft and hard urethane, and hard isocyanurate segments. RIM elastomers with the higher isocyanate index (lower hard urethane and greater isocyanurate segment content) displayed an unchanged T_g (glass transition temperature of soft segment) and increasing T_gh (glass transition temperature of hard segment) related to the hard urethane and isocyanurate segments. This is due to the phase separation between the soft and the hard segments. Cast elastomers synthesized from the higher amount of 1,4-butanediol (greater hard urethane and less hard isocyanurate segment content) showed an increasing T_gs, decreasing T_gh of hard urethane segments, and an unchanged T_gh of isocyanurate segments. This is related to the phase mixing between the soft and the hard urethane segments and the phase separation of hard isocyanurate and hard urethane segments.