低模量聚酯型PU弹性体力学性能的研究

以聚楷酯二醇、甲苯二异氰酸酯（TDI）和扩链剂为原料,制备浇注型PU弹性体,研究了预聚法和一步法、聚酯与聚醚、80/20-TDI和2,4-TDI、聚酯二醇的种类及其相对分子质量、弹性体交联点相对分子质量和硬段质量分数对弹性体力学性能的影响。结果表明,采用预聚法,以聚酯和80/20-TDI为原料合成的PU弹性体的综合性能较好。3种聚酯型PU弹性体中,聚丁二醇己二酸酯二醇的PU弹性体的综合力学性能最好。交联点相对分子质量为4500时,PU弹性体的强度为最大值。     

Hydrolytic resistance of model poly(ether urethane ureas) and poly(ester urethane ureas)

Poly(ester urethane ureas) (PesURUs) and poly(ether urethane ureas) (PetURUs) synthesized from diphenylmethane-4,4′-diisocyanate and poly(butylene adipate) diol, and poly(tetramethylene oxide) diol or poly(propylene oxide) diol, respectively, were hydrolyzed at 70°C for various periods up to 16 weeks. Differences in thermal and mechanical properties of as-received dry samples are correlated with the number and strength of hydrogen bonds formed between urea/urethane groups of hard segments and polyester or polyether groups of soft segments. Gel permeation chromatography measurements show that the molar mass of linear PesURUs markedly decreases with the hydrolysis time, whereas that of linear PetURUs remains almost unaffected. PesURU crosslinked by polymeric isocyanate has lower crystallinity, but shows somewhat better resistance to hydrolysis than its linear counterpart because of its more stable three-dimensional molecular structure. Water uptake at 37°C, dynamic mechanical thermal analysis, and differential scanning calorimetry thermograms determined for redried hydrolyzed specimens concurrently show that advancing hydrolysis accounts for decrease in the crystallinity (if any) of soft polyester segments, in the efficacy of hydrogen bonding and in crosslinking density. Experimental data indicate that hydrolytic resistance of PetURUs is primarily determined by (1) the hydrolytic stability of individual types of present groups, (2) steric hindrances affecting the access of water molecules to these groups, and (3) the hydrophilicity of backbones. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 577–586, 1998     

聚碳酸酯聚氨酯的结构及性能

引言 聚氨酯由于具有很好的生物相容性和血液相容性,加上优异的机械强度和耐挠屈性[1-2],很早就作为医用材料受到人们的重视.过去很多研究工作集中在对聚醚型聚氨酯的合成方面[3-5],但大量研究表明,聚醚聚氨酯容易在血液中巨嗜细胞所产生氧自由基的作用下氧化降解,导致生理条件下的应力开裂.与聚醚聚氨酯相比,聚碳酸酯聚氨酯(PCNU)在小直径血管和内部血管治疗中,显示出了更好的向内生长能力,且有较低的水透过率,后者对永久人工心脏的制造有着极为重要的意义.     

Preparation of epoxidized cardanol butyl ether as a novel renewable plasticizer and its application for poly(vinyl chloride)

A new type of plasticizer, epoxidized cardanol butyl ether (ECBE), was synthesized via etherification and epoxidation. Successful synthesis was confirmed from Fourier transform infrared, ¹H NMR and ¹³C NMR spectra. The obtained product was evaluated by adding it to poly(vinyl chloride) (PVC) incorporated with dioctyl phthalate (DOP). Mechanical and thermal properties of PVC blends were studied using tensile testing, thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Processability, migration and volatility of plasticizing systems were also investigated. Tensile tests found a maximum increase of 17.8% in elongation at break. DMA results indicated that glass transition temperature shifted to lower temperature with a maximum decrease of 5.76 °C. TGA results revealed that PVC blends with higher content of ECBE had higher thermal stability; initial degradation temperature, 50% weight loss temperature and the first peak degradation temperature increased by 15.3, 14.8 and 4.1 °C, respectively. Processing time was extended from 11.56 to 59.94 min. The plasticizing performance of migration and volatility resistance were higher than those of neat DOP. © 2016 Society of Chemical Industry     

Synthesis and properties of urethane elastomer-modified epoxy resin having hydroxymethyl group

Synthesis and properties of urethane elastomer-modified epoxy resins were studied. The urethane elastomer-modified epoxy resins were synthesized by the reaction of a 4-cresol type epoxy compound having hydroxymethyl groups (EPCDA) with isocyanate prepolymer. The structure was identified by IR, ¹H NMR and GPC. These epoxy resins (EPCDATDI) were mixed with a commercial epoxy resin (DGEBA) in various ratios. The mixed epoxy resins were cured with a mixture of 4,4′-diaminodiphenylmethane and 3-phenylenediamine (molar ratio 6:4) as a hardener. The curing behaviour of these epoxy resins was studied by DSC. The higher the concentration of EPCDATDI, the higher the onset temperature and the smaller the rate constant (k) of the exothermic cure reaction were. It was considered that the ratio of hydroxymethyl group to epoxide group was very small and the molecular weight of EPCDATDI was large. Therefore, the accelerating effect of the hydroxymethyl group on the epoxide–amine reaction was cancelled by the retardant effect of increased molecular weight and viscosity, and decreased molecular motion. Toughness was estimated by Izod impact strength and fracture toughness (K_1C). On addition of 10 wt% EPCDATDI with low molecular weight (M?_n 6710, estimated by GPC using polystyrene standard samples), Izod impact strength and K_1C increased by 70% and 60%, respectively, compared with unmodified epoxy resin. Glass transition temperatures (T_g) for the cured epoxy resins mixed with EPCDATDI measured by dynamic mechanical spectrometry were the same as those of unmodified epoxy resin. The storage modulus (E′) at room temperature decreased with increasing concentration of EPCDATDI. Toughness and dynamic mechnical behaviour of cured epoxy resin systems were studied based on the morphology.     

Poly(hexane succinate) plasticizer designed for poly(vinyl chloride) with a high efficiency,nontoxicity, and improved migration resistance

Poly(hexane succinate) (PHS) was designed as an alternative type of polyester plasticizer for the modification of poly(vinyl chloride) (PVC). The plasticizing effect of PHS was studied and compared with the traditional dioctyl phthalate (DOP) plasticizer. The results show that the PVC plasticized by PHS had the lowest tensile strength of 15.3 MPa and the highest elongation at break of 105.1% when 35 phr PHS was added. It also exhibited a lower glass‐transition temperature than PVC plasticized by DOP (PVC–DOP); this could be explained by the improvement of free volume for the amorphous part of PVC enhanced by high‐molecular‐weight PHS. The migration‐resistant properties of PVC–PHS was greatly superior to those of PVC–DOP. All of these results illustrate that PHS had a higher plasticizing efficiency than DOP for PVC. PHS could be used as an alternative plasticizer to remove the potential health risks of phthalates migrating out during applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46388.     

甘油酯型聚氯乙烯增塑剂的研究

以甘油、苯甲酸和乙酸为原料合成了苯甲酸乙酸甘油酯,采用FTIR和力学性能测试研究了合成产物的结构及其对聚氯乙烯的增塑性能.结果表明,合成的苯甲酸乙酸甘油酯对PVC具有优良的增塑性能.     

PVC基热塑性弹性体的制备

采用机械共混法制备PVC基弹性体，研究了聚合物的质量配比、增塑剂的用量及增塑剂的配合使用对体系性能的影响，并考察了填料对体系性能的影响。结果表明，通过不同的聚合物质量配比、增塑剂的选择以及不同填料的选用，可制得不同性能的热塑性弹性体。     

Ternary elastomer nanocomposites based on NR/BR/SBR: Effect of nanoclay composition

Elastomer nanocomposites based on natural rubber (NR), butadiene rubber (BR), and styrene butadiene rubber (SBR) containing Cloisite 15A were prepared using a two‐roll mill. Mechanical, morphological, and rheological characterization of the prepared nanocomposites was carried out in order to study the effect of different nanoclay compositions, i.e., 1, 3, 5, 7, and 10 wt %. Intercalation of the elastomer chains into the silicate layers was evidenced by d‐spacing values calculated according to the results of the X‐ray diffraction (XRD) patterns. This was directly confirmed by transmission and scanning electron microscopy (TEM and SEM). The results depict a decreasing trend in the optimum cure time (t₉₀) and scorch time (t₅) values of the nanocomposite samples with increasing nanoclay loading; where the elastic modulus (G′) and complex viscosity (η*) of the samples considerably increased. The mechanical properties of the nanocomposites show a considerable increase in the tensile modulus of NR/BR/SBR/Cloisite 15A nanocomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of urethane group on properties of crosslinked polyurethane elastomers

Three series of weakly crosslinked polyurethanes based on a hydroxyterminated polybutadiene, hydroxyterminated butadiene–acrylonitrile copolymer, and hydroxyterminated ethylene–adipate–maleate–fumarate copolymer were prepared while varying the hard segment content between 1.72 and 2.36 mol ? NH? COO? /1000 g polymer. Information on the microphase structure and the properties of the synthesized polyurethanes was obtained by differential scanning calorimetry, wide‐angle X‐ray scattering, and mechanical studies. Up to a urethane concentration of around 2 mol ? NH? COO? /1000 g polymer, there is a mixture of hard–hard and hard–soft segments. Above this concentration a large part of the hard–soft segments passes into hard–hard crystallites, liberating the soft segments. The best mechanical properties of the studied polyurethanes were found for a urethane concentration of around 2 mol ? NH? COO? /1000 g polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1858–1867, 2003     

胶粉基热塑性弹性体的研究与应用进展

概述了胶粉基热塑性弹性体的制备方法,分析了胶粉基热塑性弹性体性能的影响因素,介绍了各种改善胶粉和塑料基体的界面性能的方法,并讨论了此类热塑性弹性体的重复加工性能。展望了胶粉基热塑性弹性体的发展前景和胶粉基热塑性弹性体未来研究方向。     

A new biobased plasticizer for poly(vinyl chloride) based on epoxidized cottonseed oil

The use of epoxidized cottonseed oil as plasticizer for poly(vinyl chloride) was studied. The plasticizer content was set to 70 phr and the optimum isothermal curing conditions were studied in the temperature range comprised between 160 and 220 °C with varying curing times in the 7.5–17.5 min range. The influence of the curing conditions on overall performance of cured plastisols was followed by the evolution of mechanical properties (tensile tests with measurements of tensile strength, elongation at break, and modulus), change in color, surface changes of fractured samples by scanning electron microscopy (SEM), thermal transitions by differential scanning calorimetry, and migration in n‐hexane. The optimum mechanical features of cured plastisols are obtained for curing temperatures in the 190–220 °C range. For these curing conditions, fractography analysis by SEM gives evidences of full curing process as no PVC particles and free plasticizer can be found. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43642.     

四氢呋喃聚醚型聚氨酯弹性体力学性能的研究

介绍了以四氢呋喃聚醚（PTMG）、二异氰酸酯（MDI和TDI）、MOCA、1，4－丁二醇为主要原料合成聚醚型聚氨酯弹性体，讨论了不同的游离－NCO的加入量、不同体系（MDI／1，4－BDO、TDI／MOCA）、不同聚合方法（预聚物法、半预聚物法）及改性剂对聚氨酯弹性体哲理机械性能的影响。     

Synthesis and characterization of epoxidized neem oil: A bio-derived natural processing aid for elastomer

Low cost and environment-friendly bio-oils are gaining market value as a plasticizer for elastomeric compounds. Unsaturated triglycerides of bio-oils can be easily modified in various ways, like epoxidation, esterification, and so on. In the present work, 15 mole percentage of the total double bond content of the neem oil (NO) was epoxidized by acetic acid-hydrogen peroxide system to synthesize epoxidized neem oil (ENO). NO and ENO were characterized by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. The effect of ENO on the properties of nonpolar styrene butadiene rubber (SBR) and polar nitrile rubber (NBR) was investigated. Tear strength (69.9 N/mm), abrasion resistance index (ARI) (68.2) and hardness (64 shore A) of the SBR/ENO compound were comparable to the compound containing total distillate aromatic extract (TDAE) (values: 70.8 N/mm, 68.0 and 64 shore A respectively). Tensile strength and ARI of conventional NBR/dioctyl phthalate (DOP) compound were 24.9 MPa and 107 respectively, whereas NBR/ENO compound showed improved tensile strength (26.9 MPa), and ARI (138). Tear strength (83.4 N/mm) and hardness (74 shore A) of NBR/ENO were comparable to the tear strength (83.5 N/mm) and hardness (74 shore A) of NBR/DOP compound. Hence, the multifunctional additive property of ENO makes it a cheap and sustainable replacement of TDAE and DOP.     

Epoxidized dimeric acid methyl ester derived from rubber seed oil and its application as secondary plasticizer

A novel plasticizer epoxidized dimeric acid methyl ester (EDAMe) based on rubber seed oil was synthesized. Chemical structure of EDAMe was characterized by Fourier transform infrared (FTIR) and gel permeation chromatography (GPC). Effects of EDAMe as secondary plasticizer and its substitution of commercial plasticizer dioctyl terephthalate (DOTP) in soft poly(vinyl chloride) (PVC) films were studied. The thermal properties, mechanical properties and migration stabilities of PVC films were explored with DMA, TG, TG–FTIR, dynamic thermal stability analysis, tensile and migration tests. The results indicated that the epoxidized rubber seed oil based ester has significantly higher thermal stability than DOTP. When DOTP was substituted with 20% (m/m) EDAMe, the results of initial decomposition temperature (T_i), 10% and 50% mass loss temperatures (T₁₀ and T₅₀), and the first maximum weight‐loss temperature rate (T_P1) reached 267.2 °C, 263.5 °C, 307.3 °C and 298.9 °C, respectively. Furthermore, flexibility of the obtained PVC films enhanced significantly with the adding of EDAMe. The migration stabilities of EDAMe was also investigated and showed good migration resistance. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43668.     

不同无机填料在聚氨酯弹性体中的性能对比

以聚醚N-204、甲苯二异氰酸酯为原料,用1,4-丁二醇为扩链剂,填充经超声波分散、偶联处理的不同无机填料,分别合成填充型聚氨酯(PUR)弹性体。研究了填充型PUR弹性体的耐磨性、力学性能以及填料在弹性体中的分布状况。结果表明,不同无机填料在PUR弹性体中所表现出的性质不同,碳化硅主要提高了弹性体的耐磨性,而陶瓷微珠、玻璃微珠在增强增韧方面发挥了作用。     

松香酯在弹性体型压敏胶中的应用研究

研究了不同软化点的松香树脂作为增粘树脂用于弹性体型压敏胶带中,结果表明:液态树脂可保持胶粘剂的不干性及润湿被粘物表面的性能。低软化点树脂可使胶带有良好的粘着性,高软化点树脂保持良好的内聚力;不同软化点的松香酯在弹性体中配合得当,可以获得性能全面的压敏胶粘带。     

Synthesis and characterization of novel pentaerythritol ester as PVC plasticizer

A novel bio‐based PVC plasticizer, levulinic acid pentaerythritol ketal ester (LAPKE), was synthesized and evaluated as renewable resource alternatives to traditional phthalate. The structure of LAPKE was characterized by FT‐IR, ¹H NMR, and ¹³C NMR. The LAPKE and dioctyl phthalate (DOP) at different mass ratio were added to the PVC to prepare PVC samples. The mechanical properties of PVC samples at mass ratio of 1:1 showed that its tensile strength, elongation at break was up to an optimum value. The thermal stability was measured by dynamic thermal stability and thermogravimetric analysis (TGA), and the results showed that the thermal ability of PVC was improved with the addition of LAPKE. The weight loss of migration property (volatility, leaching test and exudation) has also increased by increasing mass ratio of LAPKE. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44227.     

聚烯烃弹性体/聚丙烯热塑性弹性体的制备及力学性能

以过氧化物为硫化剂,用动态硫化法制备了聚烯烃弹性体(POE)/聚丙烯(PP)热塑性弹性体,研究了硫化剂用量、填料种类和加工次数对体系力学性能的影响。结果表明,增加硫化剂用量可以提高体系的拉伸强度,降低拉伸永久变形和压缩永久变形。碳酸钙和滑石粉对POE/PP体系无明显增强作用,炭黑的增强作用较此二者明显一些,这三种填料加入后都会使体系的扯断伸长率降低而硬度增大。加入石蜡油会使体系的扯断伸长率和压缩永久变形增大、硬度和拉伸强度降低。加工次数对POE/PP体系的力学性能无明显影响,说明体系具有较好的重复加工性能。