Controlling the morphology of polyurethane/polystyrene interpenetrating polymer networks for enhanced blood compatibility

Polyurethane (PU)/polystyrene (PS) IPNs were simultaneously synthesized at 80°C, controlling the reaction kinetics to change the morphology. Polymerization kinetics of styrene was controlled by the content of initiator, and that of polyurethane by the catalyst concentration. The effect of the initiator and the catalyst on the polymerization rate was analyzed by NMR spectroscopy and FTIR. Gelation time was also measured by using the advanced rheometric expansion system (ARES). Samples with sea‐and‐island morphology were obtained, when the polymerization rate of PS was relatively slow, and the phase separation time was long. When the polymerization rate of PS was relatively fast, and the phase separation time was short, cocontinuous morphology was obtained. The degree of phase separation and surface roughness decreased, as the rate of PU network formation was increased, and the phase‐continuity was increased. The in vitro blood‐compatibility tests showed that the surface roughness was an important factor on the adsorption of fibrinogens and platelets. A large amount of fibrinogens and platelets were adsorbed on the relatively rough surface of samples showing sea‐island morphology. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 379–387, 2002; DOI 10.1002/app.10358     

Structure and thermal properties of PU/P(BMI–UBMI) IPNs

The preparation of polyurethane/poly(bismaleimide–urethane bismaleimide) [PU/P(BMI–UBMI)] IPNs were carried out in two steps. The two-network interaction and the morphology of PU/P(BMI–UBMI) IPNs were characterized by FTIR and TEM. The effect of the interpenetration of P(BMI–UBMI) and PU on the hydrogen bonds of N—H and the pyrolysis procedure of PU/P(BMI–UBMI) IPNs were investigated by DSC and TG. The results indicate that the interpenetration of P(BMI–UBMI) and PU reinforces the hydrogen bonding of N—H, and the incorporating of UBMI enhances the compatibility of the two networks, leading to ideal interpenetrating, which weakens the force constant of C—N—C in maleimide rings. The morphology of PU/P(BMI–UBMI) IPNs shows multiphase domains which have an obvious phase interface. The domains are connected to each other and the domain dimensions are far smaller than those of PU. The thermal weight loss shows obvious stages at different pyrolysis periods. The thermal stability of PU/P(BMI–UBMI) IPNs are much better than that of PU given the content and crosslink density of P(BMI–UBMI) in a certain range. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1689–1694, 1998     

环氧/聚氨酯梯度互穿网络聚合物冲击性能研究

研究了采用梯度IPNs方法提高环氧树脂的冲击性能,设计了新型梯度组分分布数学模型描述梯度组分的分布,采用梯度因子和梯度层数控制梯度IPNs的结构变化。并采用逐层浇铸的方法制备了不同种类的环氧/聚氨酯(EP/PU)梯度互穿网络聚合物(IPNs)材料,同时对其冲击性能进行了研究。研究结果表明,梯度结构的变化对其冲击性能有所影响,梯度层数越多,梯度因子越大,梯度IPNs的冲击强度越大。在质量比相同的情况下,梯度IPNs的冲击性能要高于普通IPNs和环氧。     

Studies on compatibility of biodegradable starch/polyvinyl alcohol blends

Compatibility of starch/polyvinyl alcohol (PVA) blends, prepared by solution cast method, is dependent on the blend composition. Crystallinity of the blend, as measured by X‐ray diffraction (XRD) and differential scanning calorimeter (DSC), decreases with increase in starch content. Thermogravimetric analysis (TGA) shows that the broadness in the peak width at the degradation region increases with increase in starch content in the starch/PVA blend. Dynamic mechanical thermal analysis (DMTA) reveal that the broadness of the relaxation peaks is due to the partial compatibility of the glycerol plasticized starch/PVA blends. The tensile property decreases with increase in starch content and the 30/70 starch/PVA blend shows maximum ductility in respect to both the percentage of elongation and energy at break. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

二氧化双环戊二烯环氧树脂/聚氨酯互穿聚合物网络的制备及其性能

以N-对羧基苯基马来酰亚胺(CPMI)和乙二醇单双环戊二烯基醚(EMDCPE)为单体合成了新型共聚物(CPMI-co-EMDCPE),将其作为二氧化双环戊二烯环氧树脂(DCPDE)/聚氨酯(PU)互穿聚合物网络(IPNs)体系的固化剂,以期改善互穿聚合物网络之间的相容性和热性能.采用红外光谱法对固化剂及互穿聚合物网络的结构进行表征.对不同固化体系涂膜的热稳定性、力学性能和微观形貌进行了研究.研究表明,互穿聚合物网络的形成,提高了二氧化双环戊二烯环氧树脂的弯曲强度、附着力和抗冲击强度.新型固化剂的加入普遍提高了二氧化双环戊二烯环氧树脂/聚氨酯互穿聚合物网络的耐热性能,增韧改性后的环氧树脂呈现明显的两相结构.     

Mechanical,thermomechanical, and morphology of PVC/PBMA blends and full IPNs

Blends and full IPNs' of poly(vinyl chloride) and polybutylmethacrylate (PBMA) have been synthesized and characterized with respect to their mechanical, thermomechanical, and morphological properties. Both the systems displayed a rise in the modulus and ultimate tensile strength and a consequent decreasing tendency of elongation at break and toughness are exhibited. The influence of crosslinking of the two polymers as has been done in case of full IPNs over the ordinary blends is quite well understood from these properties. The thermomechanical analysis revealed a substantial rise in stability with increasing methacrylate concentration in the system and this is quite apparent from the softening characteristics of the different samples under study. The biphasic cocontinuous systems as explicit from the morphological studies support phase mixing at the initial stages, with subsequent phasing out tendency with increasing percentage of PBMA incorporation. The thermomechanical parameters are in conformity to their mechanicals which have been further supported by their morphological studies. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Preparation of cellulose graft copolymers having polypeptide side chains and their blood compatibility

Blood compatibility of cellulose graft copolymers with poly(γ-benzyl-L -glutamate) and poly(N⁵-2-hydroxyethyl-L -glutamine) (Cell-g-PBLG and Cell-g-PHEG) was examined in vivo blood tests. For this purpose, Cell-g-PBLG graft copolymers with PBLG contents ranging from 7 to 60 mol % were prepared by polymerizing N-carboxy-γ-benzyl-L-glutamate(γ-BLG NCA) using aminoethyl cellulose (AE-Cell) with degree of substitution of 0.05 as macroinitiator. Graft copolymerization was carried out under a variety of conditions at 20°C in dimethyl-sulfoxide. Monomer conversion higher than 60% were obtained for all the polymerization runs. The solubility tests revealed that all of the AE-Cell and the polypeptides formed were grafted. The Cell-g-PHEG graft copolymers were prepared by treating Cell-g-PBLG graft copolymers with 2-amino-1-ethanol. Characterization of these graft copolymers were carried out by IR spectroscopy, DSC, and water content measurement. Tests for blood compatibility, in vivo, were made by a method of peripheral vein indwelling suture which was developed by one of the authors. The coating of graft copolymers on the polyester suture was made by casting either from formic acid solution of LiCl/dimethylacetamide solutions using water as the regenerating medium, and the polymer-coated sutures were implanted into a jugular and femoral vein of a dog. The results showed that the graft copolymers examined have excellent antithrombogenic properties.     

Synthesis and performance of a modified polycarboxylate dispersant for concrete possessing enhanced cement compatibility

It is well established that the performance of polycarboxylate (PCE) superplasticizers can be severely affected by the composition of individual cements. Here, a novel allylether/maleic anhydride (APEG)‐based PCE was synthesized using allyl maleate monomer as a new, additional building block. When polymerized into the PCE main chain, this building block was found to form a cyclic lactone structure. The resulting PCE molecule was tested with respect to the dispersing force in cements possessing different phase compositions and alkali sulfate (K₂SO₄) contents. These data were compared with those from conventional APEG‐ and methacrylate ester (MPEG)‐type PCEs. Results obtained from cement paste flowability and adsorption measurements suggest that the modified PCE disperses all cement samples well and hence is more robust against variations in cement composition. Apparently, the new building block induces a higher affinity of the polymer to the surface of cement and can form a denser polymer layer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and crystalline morphology of biodegradable starch/clay nanocomposites

An organically modified clay (o-clay) and a pristine clay (p-clay) were used to prepare biodegradable thermoplastic starch (TPS)/clay nanocomposites by melt processing. The gelatinization behaviour of starch with glycerol/H₂O was investigated and the gelatinized temperature (T_gel) was determined using a polarized optical microscopy (POM) equipped with a hot stage. The morphologies of gelatinized starch and extruded starch were revealed by scanning electron microscopy (SEM). Thermal stabilities of starch/clay nanocomposites were evaluated under N₂ atmosphere using thermogravimetric analysis (TGA). Transparent films of starch/clay hybrids were fabricated by hot pressing. Intercalation of starch into clay galleries and crystalline structure of starch were investigated using X-ray diffraction (XRD). It was found that the increase in d-spacing of organically modified clay was due to starch molecular intercalation while the increase in d-spacing of pristine clay was mostly caused by glycerol intercalation because of the narrow valid d-spacing of pristine clay and special ring-like monomer of starch. The mechanism of starch intercalation in clay galleries was discussed.     

丁腈橡胶/聚氨酯复合材料用相容剂的合成及复合材料的性能研究

利用端羟基液体丁腈橡胶（HTBN）分别与二苯基甲烷二异氰酸酯（MDI）和对氯苯基异氰酸酯（4CPI）反应制备HTBN-聚氨酯（PU）和HTBN-4CPI两系列相容剂,研究其对采用机械共混法制备的丁腈橡胶（NBR）/PU复合材料性能的影响。结果表明：加入相容剂后,NBR和PU的相容性得到有效改善,NBR/PU复合材料的拉伸强度和储能模量增大,磨耗性能提高,当HTBN-4CPI质量分数为0.98%时,NBR/PU复合材料的拉伸强度和储能模量最大,磨耗性能最佳,其中拉伸强度增大35%,磨耗量减小56%。     

聚氨酯-聚丙烯酸互穿网络聚合物乳液的合成

以甲苯二异氰酸酯、聚醚多元醇、二羟甲基丙酸、1,4 丁二醇、甲基丙烯酸甲酯、甲基丙烯酸丁酯等为原料,采用原位乳液聚合工艺合成聚氨酯聚丙烯酸酯乳液.研究了单体含量对乳液及胶膜性能的影响.实验结果表明:随着乙烯基单体含量的增加,乳液稳定性下降;胶膜的断裂伸长率降低,硬度和耐水性增加.当乙烯基单体的质量分数为35%时,乳液的稳定性大于365 d,胶膜的断裂伸长率为482%,摆杆硬度为0.68,吸水率为18.7%.红外光谱分析表明合成了聚氨酯聚丙烯酸酯.     

POM／PU共混物增容剂的合成与应用

本文以酸为催化剂，将甲醛与一缩乙二醇缩合聚合，缩合物经ＴＤＩ封端，１，４－丁二醇扩链合成了ＰＯＭ／ＰＵ共混物的增容剂ＰＯＵ。利用化学分析法、红外光谱法对合成的ＰＯＵ增容剂进行了表征；借助扫描电子显微镜，差分析仪分析了共混物的微观结构形热行为，并对共混物的力学性能进行了系统研究。研究发现ＰＯＵ的加入使分散相颗粒尺寸明显减小，使三元共混物中ＰＯＭ的烷点降低，并使三元共混物的拉伸强度、缺口冲击强度、断裂     

Effect of OMMT on the phase morphology controlling of PU/EP IPN

Organic montmorillonite (OMMT) modified polyurethane (PU) /epoxy resin (EP) (OMMT-PU/EP) graft interpenetrating polymer network nanocomposites with different content of OMMT were prepared. The effect of the OMMT content on the phase behavior of the PU/EP IPN system has been studied by Dynamic mechanical analysis (DMA). With the content of OMMT increased, the tan δ turned from single peak to two peaks and the damping temperature range became wider when the isocyanate index is low. Transmission electron microscope (TEM) and atomic force microscope (AFM) results showed that high content of OMMT favored phase separation to form a larger-size domain in nanocomposites, resulting in the broadening of damping temperature range. This work demonstrates that we can control phase behaviour of OMMT-PU/EP IPNs by changing the OMMT content. This result provides potential opportunity for this type of materials to be used as sound and vibration damping polymers over wide temperature ranges.     

Synthesis and characterization of quaternary ammonium PEGDA dendritic copolymer networks for water disinfection

Quaternary ammonium compounds are some of the most widely used antimicrobial agents for various medical applications due to their low toxicity and broad spectrum antimicrobial activity. Various generations of poly(ethyleneglycol)diacrylate (PEGDA) based dendrimers were synthesized by Michael addition reaction of PEGDA with ethylene diamine and diethyl amine. The percentage yield of different generation of dendrimers were 70%, 66%, 60%, and 85% for G1.0 (=), G1.5 (NH₂), G2.0 (=), and G2.5 (=, NEt₂), respectively. Synthesized dendrimers were also copolymerized with ethyleneglycol dimethacrylate by free radical bulk polymerization at room temperature using ammonium persulphate/N,N,N′,N′‐tetramethyl ethylenediamine as a redox initiator system to form dendritic copolymer networks. These networks were quaternized with hydrochloric acid by continuously refluxing at 40°C for 6 h. Dendrimers and quaternized dendritic copolymer networks were characterized by ¹HNMR, FTIR, Differential scanning calorimetry, Thermogravimetric analysis, Scanning electron microscope, swelling, and leaching studies. Synthesized quaternary ammonium dendritic copolymer networks were found to be biostable and insoluble in water and capable of killing both Gram‐positive and Gram‐negative bacteria when contaminated water was treated with them. It was also observed that antimicrobial efficiency of dendritic copolymer networks increases with the increase in nitrogen atoms in the copolymer. The dendritic copolymer network with 16 quaternary ammonium groups (G2.5 (=, NEt₂): EGDMA QHCl) were highly efficient to disinfect 10 mL bacterial solution of 2000 cfu/mL within 2 min even at a very low concentration of 0.005 g/mL. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

PU／EP／PBA三元IPN弹性体的合成与表征

合成了以ＰＵ为第一网络的ＰＵ／ＥＰ／ＰＢＡ三元同步ＩＰＮ弹性体,并通过密度测试、红外光谱分析、玻璃化转变行为、溶剂萃取以及电镜分析等手段对体系进行了表征。实验证明,通过改变多种合成条件,在不引入电荷的情况下仍仍可得到宏观的一透明的体系,同时体系的红外光谱谱图的单一玻璃化转变温度以及试样良好的耐溶剂性都充分证帝了体系具有互穿特征。     

Miscibility, properties and morphology of biodegradable blends of UHMW-PPC/PVA/EVOH

Thermally stable and biodegradable blends of ultrahigh molecular weight poly(propylene carbonate) (UHMW-PPC), poly(vinyl alcohol) (PVA) and poly(ethylene-co-vinyl alcohol) (EVOH) were melt compounded in a batch mixer followed by compression molding. The miscibility, mechanical properties, thermal behavior, and morphologies of the blends were investigated by torque rheometer, Fourier transform infrared spectroscopy, tensile strength test, thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy. The experimental results showed well interfacial miscibility among phases of PVA, EVOH and PPC. The hydrogen bonding interaction between PPC with PVA and/or EVOH can also be confirmed by Fourier transform infrared spectroscopy spectra. The study on the mechanical properties and thermal behavior demonstrated that PVA/EVOH content can enhance the tensile strength, thermal stability and crystallinity of the blends dramatically. Further, scanning electron microscopic observation revealed a three-phase structure with good interfacial adhesion.     

Single crystals morphology of biodegradable double crystalline PLLA-b-PCL diblock copolymers

The morphology of solution grown single crystals of a series of double crystalline diblock copolymers derived from l-lactide and ?-caprolactone has been investigated by means of transmission electron microscopy. The copolymers had a variable composition with a poly(l-lactide) weight percentage that ranged between 81 and 10%. All samples had a low polydispersity index (1.4-1.1) and a similar number average molecular weight (20,000-35,000 g/mol).Bulk crystallization and melting behaviour of diblock copolymers were evaluated by DSC and the results demonstrated the double crystalline nature of the samples. Fractionated crystallization clearly occurred in copolymers having an intermediate composition.Isothermal crystallizations were performed in dilute n-hexanol solutions at temperatures that ranged between 80 and 50 °C. Crystal morphologies were dependent on the crystallization temperature and even on the composition. Thus, the inability of poly(?-caprolactone) (PCL) blocks to crystallize between 80 and 70 °C rendered lozenge, truncated and spindle-shaped crystals associated to the poly(l-lactide) (PLLA) block. These usually had thicker edges due to PLLA overgrowths that mainly took place in their periphery. However, an overgrowth of irregular PCL crystals during subsequent cooling and crystallization at room temperature was also detected. Complex morphologies constituted by lamellar crystals of both PCL and PLLA blocks were developed at intermediate temperatures (70-65 °C), whereas elongated hexagonal morphologies mainly associated to the PCL block were detected at the lowest crystallization temperature. In general, electron diffraction patterns showed for all samples’ reflections associated to both poly(?-caprolactone) and poly(l-lactide) (α-form) crystals. The relative intensity between the two types of reflections varied according to the copolymer composition.     

新型双组分聚氨酯改性固化交联剂的合成

合成了一种改性TDI-TMP加成预聚物并研究了其在聚氨酯木器涂料中的具体应用;实验表明,该加成预聚物具有良好的贮藏稳定性,配漆后混合液低粘高固、刷涂性好,漆膜丰满度佳和耐冲击性优及较好的耐候性,并且,性价比高,完全可以替代普通的TDI-TMP加成物。     

水性聚氨酯的合成与改性

对水性聚氨酯的合成单体、合成原理、合成工艺及改性方法作了介绍。水性聚氨酯合成技术不断完善,市场正在推进,国内相关企业和研究机构应加强合作,从分子设计出发,不断推进水性聚氨酯产业的技术进步和市场推广。     

Preparation and blood compatibility of carbon/TiO2 nanocomposite

A carbon/TiO₂ nanocomposite, which consists of carbon film with various sp³C content and TiO₂ nanowire arrays, has been synthesized, in which the top surface of TiO₂ nanowire arrays prepared using hydrothermal method on fluorine-doped tin oxide glass were coated with carbon thin films. The carbon thin films with a higher, medium and lower sp³C content were deposited by pulsed magnetic filtered cathodic vacuum arc deposition, plasma-enhanced chemical vapor deposition and magnetron sputtering deposition, respectively. The surface morphology and structure of TiO₂ nanowire arrays were investigated by scanning electron microscopy, transmission electron microscope and X-ray diffraction. The sp³C content in carbon films was characterized using Raman spectroscopy. The blood compatibility of the samples including the TiO₂ nanowire arrays, carbon films and carbon/TiO₂ nanocomposite was assessed by tests of platelet adhesion in vitro. Results showed that the carbon/TiO₂ composite can effectively improve the anticoagulant function compared to the single materials. It is believed that the excellent blood compatibility of the carbon/TiO₂ nanocomposite is attributed to a joint function of surface properties adjusted by nanowire arrays and electronic structure of carbon thin films.