高力学性能线性聚氨酯脲的合成与优化

聚乙二醇(PEG400)助引发DL-丙交酯形成的大分子二醇,经1,6-六亚甲基二异氰酸酯(HDI)偶联、哌嗪(PPZ)扩链后制得线性嵌段聚氨酯脲(PEG400-PUU-PPZ)。因PEG400的增韧作用和PPZ环状结构的增强作用使得PEG400-PUU-PPZ可望具有优良的力学性能。通过系统研究扩链时间(1~5h)和温度(30~60℃)对PEG400-PUU-PPZ特性黏度的影响,开发了一种梯度升温扩链的新工艺。结果表明,与恒温扩链相比,梯度升温扩链所得PEG400-PUU-PPZ的分子量更高、分子量分布更窄;相应地,其拉伸模量和屈服强度更高,表现出明显的强韧性材料的特征,可望用作骨组织修复材料。     

生物基可降解交联聚氨酯的合成及表征EI北大核心CSCD

以聚L-丙交酯(PLLA)为软段,异佛尔酮二异氰酸酯(IPDI)和甲基丙烯酸羟乙酯(HEMA)为硬段,采用两步法制备了双键封端的聚氨酯预聚物,通过UV辐射得到一种可用于生物医学材料,具有可生物降解性的交联聚氨酯(cPU)。利用核磁共振、凝胶渗透色谱、热失重及差示扫描量热分别表征了PLLA和cPU的组成、结构及热性能,此外,对cPU材料进行了力学性能和亲水性的表征及体外降解模拟实验。结果表明,增加硬段的含量,所制备的聚氨酯材料的玻璃化转变温度(Tg)和热稳定性提高,交联度、拉伸强度和降解速率增大,断裂伸长率减小;细胞实验表明,cPU材料能支持脂肪间充质干细胞(hASC)的粘附,说明cPU具有良好的生物相容性。     

HMDI型吸水膨胀聚氨酯弹性体的研制

采用4,4-二环己基甲烷二异氰酸酯(HMDI)与亲水性多元醇(PEG)合成预聚体,进一步与混合扩链剂反应,制备吸水膨胀聚氨酯弹性体。通过材料力学测试机和硬度计等仪器对拉伸强度、断裂伸长率、吸水率和硬度等性能测试。结果表明,PEG相对分子质量为2000,合成预聚体的NCO质量分数为9%,混合扩链剂n(JJ-125)∶n(TMP)=5∶5,(JJ-125为磺酸盐类亲水扩链剂)R值为1.05,制备出的吸水膨胀聚氨酯弹性体综合性能最优。     

生物相容性优异的聚碳酸酯聚氨酯的合成及其性能研究

采用溶液预聚体法以芳香族二苯甲烷二异氰酸酯(MDI)为硬段,聚碳酸酯二元醇(PCDL)为软段合成了生物相容性优异的聚碳酸酯聚氨酯,分别考虑了R值、扩链剂用量、预聚温度的单因素影响。结果表明:当n(NCO)/n(OH)值为2.0,10%的扩链剂1,4-丁二醇、采用70~80℃的预聚温度时合成的聚碳酸酯聚氨酯性能最优。力学性能测试验证其机械性能良好,拉伸强度可到21.4MPa;其水解降解80d后质量损失达16%,说明所制备的聚氨酯生物相容性及稳定性良好,可以作为一种具有广泛应用前景的生物医用材料。     

硬段类型和含量对嵌段聚氨酯脲性能的影响

以聚己二酸乙二醇-丙二醇酯二醇(PEPA)为软段,分别采用4种二胺扩链剂和3种二异氰酸酯为硬段,通过预聚体法合成了一系列不同硬段结构和含量的聚氨酯脲弹性体,并采用红外光谱、热失重分析、差示扫描量热和拉伸测试等手段,研究了硬段类型及含量对聚氨酯脲性能的影响。结果表明,在软段结构一致,硬段含量接近的情况下,兼具柔性和刚性的硬段有助于提升聚氨酯脲的力学性能、热学性能和微相分离程度。几种二胺扩链剂和二异氰酸酯中,由二苯基甲烷二异氰酸酯(MDI)和4,4'-二氨基二苯醚(ODA)构成的硬段性能最佳;在软、硬段结构一致的情况下,硬段含量对聚氨酯脲性能影响明显。随着硬段含量增加,聚氨酯脲的拉伸强度、微相分离程度先增大后减小,5%热失重温度和断裂伸长率逐渐下降。当PEPA/MDI/ODA摩尔比为1∶0.5∶0.5(硬段含量31.7%),聚氨酯脲拉伸强度达51.5 MPa,断裂伸长率为709%,5%热失重温度为282.7℃,性能最佳。     

生物基可降解交联聚氨酯的合成及表征

以聚L-丙交酯(PLLA)为软段,异佛尔酮二异氰酸酯(IPDI)和甲基丙烯酸羟乙酯(HEMA)为硬段,采用两步法制备了双键封端的聚氨酯预聚物,通过UV辐射得到一种可用于生物医学材料,具有可生物降解性的交联聚氨酯(cPU)。利用核磁共振、凝胶渗透色谱、热失重及差示扫描量热分别表征了PLLA和cPU的组成、结构及热性能,此外,对cPU材料进行了力学性能和亲水性的表征及体外降解模拟实验。结果表明,增加硬段的含量,所制备的聚氨酯材料的玻璃化转变温度(Tg)和热稳定性提高,交联度、拉伸强度和降解速率增大,断裂伸长率减小;细胞实验表明,cPU材料能支持脂肪间充质干细胞(hASC)的粘附,说明cPU具有良好的生物相容性。     

聚乙二醇-聚丁二酸丁二醇酯-聚乙二醇嵌段共聚物的合成与表征

以1,4-丁二酸(SA)和过量的1,4-丁二醇(BD)为反应物,通过熔融缩聚制备了羟基封端聚丁二酸丁二醇酯齐聚物(OH-PBS-OH),以甲氧基聚乙二醇(Me OPEG)与丁二酸酐进行半酯化得到含端羧基的预聚物,再用二氯亚砜对预聚物进行活化,得到含酰氯端基的预聚物(Me OPEG-COCl);以Me OPEG-COCl与OH-PBS-OH为反应物,通过溶液法合成聚乙二醇-聚丁二酸丁二醇酯-聚乙二醇(Me OPEG-PBS-PEGOMe)嵌段共聚物。利用红外光谱、核磁共振、差示扫描量热、广角X射线衍射、偏光显微镜等手段对共聚物的结构、结晶性能和酶降解性能进行研究。结果表明,Me OPEG-PBS-PEGOMe嵌段共聚物中,聚乙二醇(PEG)链段的引入未改变聚丁二酸丁二醇酯(PBS)链段的晶体结构,但结晶形态由球晶转变为麦穗状晶体;同PBS比较,Me OPEG-PBS-PEGOMe嵌段共聚物的结晶速率降低,酶降解速率加快。     

聚醚酯聚氨酯丙烯酸酯的合成及表征

以聚乙二醇(PEG,Mw1000)引发ε-己内酯(ε-CL)开环制得聚醚酯嵌段共聚物二醇(PCEC)软段,与二异氰酸酯(异佛尔酮二异氰酸酯和六亚甲基二异氰酸酯)和甲基丙烯酸羟乙酯反应,然后固化制得聚醚酯聚氨酯丙烯酸酯材料(PUA)。对PUA进行组成和结构的表征。结果表明,增加PCL链段能提高PUA材料的结晶度,但降低了吸水率和降解速率。PUA材料的酶解速率大于水解速率。PCEC2000-HDI材料具有优异的亲水性和降解性能,72h吸水率高达65.24%,在11周内就能在酶溶液中完全降解。该类PUA材料具有应用于组织工程材料的潜力。     

正丁胺为扩链剂合成水性聚氨酯皮革涂饰剂

采用异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)、聚四氢呋喃(PTMG)为原料制备聚氨酯预聚体,分别以乙二醇(EG)、乙二胺(EN)和正丁胺(n-butylamine)为扩链剂制备了水性聚氨酯皮革涂饰剂,研究了该涂饰剂所成膜的力学性能、断裂伸长率和吸水性。结果表明,以正丁胺为扩链剂制备的水性聚氨酯膜的断裂伸长率最好,高达1454%;其玻璃化转变温度可达-82℃,耐水性也比用其它两种扩链剂合成的产品好。     

聚碳酸亚丙酯聚氨酯弹性体的合成与性能

以聚碳酸亚丙酯二醇、二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)等为原料,采用预聚体法合成了聚碳酸亚丙酯聚氨酯弹性体(PUE-PPC)。研究表明,PUE-PPC拉伸强度和撕裂强度优于聚醚型弹性体;与聚酯型弹性体相比,具有较好的水解稳定性,经35d浸泡后,其拉伸强度保持率高出33%。研究了异氰酸酯指数(R)、预聚体-NCO基含量、扩链剂种类等对PUE-PPC力学性能的影响。结果表明,随着R值减小,弹性体的拉伸强度和撕裂强度先增大后减小,并在R=1.05时达到最大值,断裂伸长率则一直增大;随着-NCO基含量的增加,弹性体的拉伸强度和撕裂强度提高,而断裂伸长率减小;扩链剂链长越短,弹性体力学性能越好。     

催化剂对异佛尔酮二异氰酸酯制备的脂肪族聚氨酯弹性体结构和性能的影响

采用一步法通过异佛尔酮二异氰酸酯与聚丙二醇和1,4-丁二醇反应合成了脂肪族聚氨酯（PU）弹性体。考察了催化剂的种类和含量对PU弹性体结构和性能的影响。结果表明,以辛酸亚锡为催化剂时,PU弹性体的软段相和硬段相间的相分离程度最明显且分子量最低,导致其力学性能最差;以辛酸铋为催化剂时,PU弹性体软段相和硬段相的相容性较好且...     

From cellulosic waste to nanocomposites. Part 2: synthesis and characterization of polyurethane/cellulose nanocomposites

New polyurethane (PU)-based nanocomposites were synthesized through two-step in situ polymerization by incorporating low loading levels of spherical cellulose nanoparticles (CNs). Structural, mechanical, thermal, and morphological characterization of the nanocomposites was done with infrared spectroscopy, X-ray diffraction, tensile test, dynamic mechanical thermal analysis, thermogravimetry, differential scanning calorimetry, and field emission scanning electron microscopy. The results showed with incorporation of CNs there was no significant change in the structure of PU. However, the addition of 1 % CNs into PU increased the modulus nearly 42 % and tensile strength by 112 %. On the contrary, elongation at break decreased with increasing nanoparticles contents, but the nanocomposites maintained an elongation of greater than 800 %, which was still a large elongation. The thermal stability of PU enhanced with increasing the small amounts of nanoparticles. Also, incorporating of the CNs improved the phase separation between the soft and hard domains which led to an upward shift in melting temperatures and enthalpy of crystalline phase melting. These results were very encouraging in terms of using CNs as an inexpensive nanofiller and improving the mechanical and thermal properties of PU without using solvents in nanocomposite preparation.     

自修复聚氨酯防水涂料的研究

为了赋予聚氨酯防水涂料自修复性能,先用环氧树脂对高吸水纤维进行改性,再将改性纤维与双组分聚氨酯通过共混制备自修复聚氨酯防水涂料,最后用刮涂法制备防水涂层。用扫描电镜、红外光谱仪对防水涂层的微观结构进行分析,用万能材料试验机、电动不透水仪等对防水涂层的机械性能、自修复性能及防渗透性能等进行测试。结果表明,高吸水纤维、氧化锌有助于提高防水涂层的拉伸强度,防水涂层的最大抗拉强度为1.83MPa,断裂伸长率达到795%。防水涂料完全切断自修复24h后,裂口完全愈合。自修复48h后,拉伸强度恢复率最高可达63%,断裂伸长率达到60%左右。本研究为聚氨酯防水涂料自修复提供了新的方法。     

Synthesis and characterization of photoactive polyurethane elastomers with 2,3-dihydroxypyridine in the main chain

Photoactive polyurethane elastomers with pyridine derivatives in the polymer backbone were synthesized by chain-extending isocyanate end-capped prepolymers with 2,3-dihydroxypyridine. The isocyanate-terminated prepolymers were obtained from poly(tetramethylene oxide) glycol of molecular weight 1400 (Terathane 1400) and 1,6-hexamethylene diisocyanate. The properties of the linear heterocyclic polyurethane were compared with properties of the crosslinked heterocyclic polyurethane obtained by chain extension with various crosslinkers. Heterocyclic polyurethane elastomers were characterized using Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), dynamic mechanical analysis (DMA), contact angle measurements, and mechanical analysis. Static mechanical measurements showed greater elongation and tensile strength for polyurethanes with a lower content of heterocyclic groups in the hard segment. The static contact angles of the cast films of these polymers indicated that the nature of the hard segment influences the surface polarity. The dynamic mechanical spectra revealed that linear polymers have two transition temperatures as results from a clear phase separation caused by high-intermolecular hydrogen bonds in the regions of pyridine units and urethane groups. Polyurethane elastomer films with pyridine moieties in the main chain form a photosensitive material. If stored in laboratory conditions (light, ambient air atmosphere), the color of the films changes from white to black. These photo-induced structural changes are studied by H NMR measurements.     

Co-electrospun blends of PU and PEG as potential biocompatible scaffolds for small-diameter vascular tissue engineering

A small-diameter vascular graft (inner diameter 4 mm) was fabricated from polyurethane (PU) and poly(ethylene glycol) (PEG) solutions by blend electrospinning technology. The fiber diameter decreased from 1023 ± 185 nm to 394 ± 106 nm with the increasing content of PEG in electrospinning solutions. The hybrid PU/PEG scaffolds showed randomly nanofibrous morphology, high porosity and well-interconnected porous structure. The hydrophilicity of these scaffolds had been improved significantly with the increasing contents of PEG. The mechanical properties of electrospun hybrid PU/PEG scaffolds were obviously different from that of PU scaffold, which was caused by plasticizing or hardening effect imparted by PEG composition. Under hydrated state, the hybrid PU/PEG scaffolds demonstrated low mechanical performance due to the hydrophilic property of materials. Compared with dry PU/PEG scaffolds with the same content of PEG, the tensile strength and elastic modulus of hydrated PU/PEG scaffolds decreased significantly, while the elongation at break increased. The hybrid PU/PEG scaffolds demonstrated a lower possibility of thrombi formation than blank PU scaffold in platelet adhesion test. The hemolysis assay illustrated that all scaffolds could act as blood contacting materials. To investigate further in vitro cytocompatibility, HUVECs were seeded on the scaffolds and cultured over 14 days. The cells could attach and proliferate well on the hybrid scaffolds than blank PU scaffold, and form a cell monolayer fully covering on the PU/PEG (80/20) hybrid scaffold surface. The results demonstrated that the electrospun hybrid PU/PEG tubular scaffolds possessed the special capacity with excellent hemocompatibility while simultaneously supporting extensive endothelialization with the 20 and 30% content of PEG in hybrid scaffolds.     

聚氨酯-纳米CaCO3/PVC复合材料力学性能

在考察了聚氨酯-纳米碳酸钙/聚氯乙烯(PU-nano-CaCO₃/PVC)反应挤出工艺的基础上,结合PU 的反应特点,将经硬脂酸表面处理的nano-CaCO₃利用超声辐照技术并经搅拌分散于液化4,4'-二苯基甲烷二异氰酸酯(L-MDI)中,采用反应挤出一步法工艺制备了PU-nano-CaCO₃/PVC复合材料,并对其力学性能进行了研究。结果表明,PU与nano-CaCO₃的质量配比为4∶1时,对PVC的增韧效果最佳,PU与nano-CaCO₃能协同增韧PVC,且nano-CaCO₃具有补强作用。当PU/nano-CaCO₃/PVC质量比为20∶5∶75时,材料的综合性能最优,冲击强度达到58.3 kJ/m,拉伸强度为51.5MPa。     

Synthesis and characterization of novel THTPBA/PEG-derived polyurethane scaffolds for tissue engineering

Novel polyurethane (PU) scaffold materials were designed and prepared on the basis of a coupling reaction between tetra-hydroxyl-terminated poly(butadiene-co-acrylonitrile) prepolymer (THTPBA) and poly(ethylene glycol) (PEG) via 1,6-hexamethylene diisocyanate as anchor molecule. The hydrophilicity, degradability, mechanical, and biomedical properties of the THTPBA/PEG PU materials were scrutinized by swelling and goniometry, FTIR and gravimetry methods, tensile stress–strain measurements and hemolysis, platelet activation, dynamic (erythrocyte aggregation) and static coagulation as well as MTT assays. The experimental results indicated that the hydrophilicity and mass loss were enhanced with increased concentrations and molecular weight (MW) of PEG. The degradation may be attributable to the cleavage of urethane or ester bonds in polymer chains. The in vitro blood compatibility and MTT cytotoxicity investigations elicited that the MW of PEG and mass ratios of THTPBA to PEG had important influence on the biomedical properties. The tensile stress–strain investigations showed that the highly crosslinked architecture offered high elastic modulus and mechanical strength. The PU scaffolds with proper component ratios and MW of PEG exhibited improved mechanical properties and biocompatibility as well as low toxicity, and can be employed as potential candidates for blood-contacting applications.     

Effects of guar gum content on structure and properties of multi-crosslinked polyurethane composite films

Films from multi-crosslinked polyurethane with different contents of guar gum (1–10 wt%) were prepared through a solution-casting method, followed by a thermal treatment or natural light exposure crosslinking procedure. Acrylic terminated prepolymers were prepared by capping the NCO groups of polyurethane prepolymers with pentaerythritol triacrylate. The effect of the guar gum content on the miscibility, morphology and physical properties of the blend films was investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, surface properties and tensile tests. The results reveal that small guar gum content is well embedded in the crosslinked polyurethane network and forms films with good mechanical properties, thermal behavior and hydrophilic properties. These results prove guar gum to be eco-friendly filler for multi-crosslinked polyurethane network. In the case of polyether urethanes, incorporating up to 3 wt% guar gum leads to a slight enhancement of the elongation at break, while for polyester urethanes incorporation up to 3 wt% guar gum slight increases stress at break values. Incorporating guar gum into the polyurethane networks leads to an increase in the hydrophilic nature of the polymer blends and improved surface structure. The properties of guar gum – which can be abundantly found in nature – make it desirable for polymer blends for biomedical applications.     

蒙脱土改性PU/EP IPN的研究

本文通过端异氰酸酯基聚氨酯预聚体与环氧树脂E-51形成了互穿网络,并通过热重分析仪(TGA)研究了完全固化后的互穿网络的热分解行为;透射电镜研究了IPN的相分离行为及用拉伸强度,断裂伸长率对其进行了力学性能的表征.结果表明,经过环氧树脂改性的聚氨酯的耐热性能比纯聚氨酯得到了提高,且力学性能也有所改善.并选取性能较好的PU/EP IPN,用纳米级有机蒙脱土对其进行了改性.研究发现,经有机纳米蒙脱土改性的PU/EP IPN的力学性能及耐热性有了进一步的提高.