抗菌剂用于牙科复合树脂的研究进展

龋病是常见的口腔疾病,填充修复是治疗的重要手段.复合树脂凭借色泽美观和理化性能优异等特点,广泛应用于牙科修复材料中.继发龋是临床应用中导致修复失败的主要原因之一.为了抑制继发龋、延长树脂使用寿命,研发具有长期抗菌功能的牙科复合树脂具有重要意义.目前,主要通过向复合树脂体系中添加抗菌型无机粒子或抗菌型有机单体赋予材料抗菌...     

一种自引发自交联苯并口恶嗪的合成及热性能分析

苯并口恶嗪树脂(Bz)是一类耐热性很好和残炭率较高的酚醛树脂。结合光聚合技术,通过分子设计合成出具有新型功能的苯并口恶嗪单体,使用核磁氢谱和傅里叶变换红外光谱对其结构进行表征和确认。利用实时红外研究其光聚合行为,透射红外研究其热固化行为;萃取法和热重分析分别测其凝胶含量以及热稳定性。实验结果表明,合成出的新型苯并口恶嗪(BZOA)具有自引发自交联功能,双键转化率最大可达99.96%。热聚合过程中先碳碳双键反应而后开环固化,热固化产物的凝胶含量达到91.36%。随着BZOA量的增加,BZOA共聚物的残炭率(Yc)从0.48%升高到29.03%,耐热性能显著提高。     

纳米复合树脂口腔修复材料的研制及性能表征

利用纳米技术和分子组装技术,将具有生物相容性的羟基磷灰石材料作为牙齿龋洞的修复充填的无机填料,与有机树脂基质有机地复合和组装,从而开发出强度高、易加工且具有良好生物相容性的复合树脂牙齿修复材料。根据我国医药行业标准YY1042—2003《牙科学聚合物基充填、修复和粘固材料》,对纳米复合树脂材料挠曲强度、压缩强度以及吸水值等性能进行了实验室阶段的表征,性能完全达到目前临床使用的进口牙科复合树脂的各项指标。     

聚甲基苯基二苯乙炔基硅烷树脂的热稳定性与介电性能

为研究聚甲基苯基二苯乙炔基硅烷树脂的热稳定性与介电性能,以甲基苯基二氯硅烷、苯乙炔、镁条为原料,通过Grignard反应制备甲基苯基二苯乙炔基硅烷(MPDPES),再通过热聚合法制备聚甲基苯基二苯乙炔基硅烷树脂(PMPDPES).采用傅里叶变换红外光谱(FTIR)和核磁共振波谱(1 H-NMR、13 C-NMR和29 ...     

聚(甲基苯基-间乙炔基硅烷)树脂的合成及热稳定性能EI北大核心CSCD

以甲基氢二乙炔基硅烷、甲基氢二氯硅烷和二苯基二氯硅烷为主要原料,通过格氏试剂与二氯硅烷的缩合反应,合成了一种硅炔杂化耐高温树脂聚(甲基苯基-间乙炔基硅烷)(PMPS)。采用傅里叶变换红外光谱、核磁共振和凝胶渗透色谱对其结构进行了表征;利用傅里叶变换红外光谱和差示扫描量热技术分析了树脂的固化行为;采用热重分析考察了树脂固化产物的热稳定性能。结果表明,PMPS树脂的数均相对分子质量为1140,相对分子质量分布系数为1.34,常温下黏度适中,具有良好的加工性能。树脂通过硅氢加成反应和Diels-Alder反应形成交联网络结构,固化产物具有良好的热稳定性,在空气和氮气气氛中失重5%时的温度(Td5)高于550℃,1000℃的质量保留率大于65%。     

聚(甲基苯基-间乙炔基硅烷)树脂的合成及热稳定性能

以甲基氢二乙炔基硅烷、甲基氢二氯硅烷和二苯基二氯硅烷为主要原料,通过格氏试剂与二氯硅烷的缩合反应,合成了一种硅炔杂化耐高温树脂聚(甲基苯基-间乙炔基硅烷)(PMPS)。采用傅里叶变换红外光谱、核磁共振和凝胶渗透色谱对其结构进行了表征;利用傅里叶变换红外光谱和差示扫描量热技术分析了树脂的固化行为;采用热重分析考察了树脂固化产物的热稳定性能。结果表明,PMPS树脂的数均相对分子质量为1140,相对分子质量分布系数为1.34,常温下黏度适中,具有良好的加工性能。树脂通过硅氢加成反应和Diels-Alder反应形成交联网络结构,固化产物具有良好的热稳定性,在空气和氮气气氛中失重5%时的温度(Td5)高于550℃,1000℃的质量保留率大于65%。     

傅里叶变换衰减全反射红外光谱法化学试剂定性鉴别数据库的建立

使用傅里叶变换衰减全反射红外光谱法(ATR-FTIR)进行了近200种有机化学试剂的定性鉴别试验,建立了傅里叶变换衰减全反射红外光谱数据库。使用该方法能够鉴别大多数常见的有机化合物,并具有分辨力高、检验简便的特点。     

光催化下载铜凝胶对水体中六价铬离子的吸附及原位还原

分别以二水氯化铜(CuCl2 ·2H2 O)和过硫酸铵(APS)为氧化剂,将聚吡咯(PPy)均匀地分散到明胶/壳聚糖(Gel/CS)基质中,制备出了Gel/CS/PPy-C和Gel/CS/PPy-A光敏感复合水凝胶,用扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)和紫外-可见光谱(UV-Vis)对材料结构进...     

牙科复合树脂中无机填料的研究进展

牙科复合树脂是一类由有机树脂基质和经过表面处理的无机填料及引发系统组合而成的牙科修复材料。无机填料作为复合树脂的分散相,在牙科复合树脂中具有重要作用,对复合树脂的力学性能、物理性能、化学性能都有着重要的影响。介绍了无机填料的种类、形态、含量、粒径大小及其表面处理,并结合许多学者对复合树脂中无机填料的研究,探讨无机填料对复合树脂性能的影响,最后展望了复合树脂应提高的性能和无机填料努力的方向。     

硅氧树脂 Si-O 键伸缩振动模式ATR红外光谱研究

在303~393 K 温度范围内,采用变温傅里叶变换衰减全反射红外光谱(ATR-FTIR)技术分别测定硅氧树脂的一维红外光谱、二阶导数红外光谱和四阶导数红外光谱。研究发现,在1800~600 cm-1范围内,聚硅氧树脂主要存在着 CH 3伸缩振动模式(νCH3)、CH 3变形振动模式(δCH3)、CH 3摇摆振动模式(ρCH3)、Si-O 伸缩振动模式(νSi-O )和 Si-C 伸缩振动模式(νSi-C )。在1100~1000 cm-1范围内,以νSi-O 为研究对象,研究了温度对硅氧树脂分子结构的影响。实验发现,随着测定温度的升高,硅氧树脂νSi-O 的主要红外吸收频率出现了明显的红移现象。进一步研究了硅氧树脂νSi-O 的二维红外光谱,考查温度对于νSi-O 红外吸收强度的影响。研究发现,随着测定温度的升高,硅氧树脂νSi-O 红外吸收强度的变化快慢顺序为：1024 cm-1>1096 cm-1>1010 cm-1>1076 cm-1>1083 cm-1>1064 cm-1。本研究拓展了 ATR-FTIR 技术在硅氧树脂材料热变性方面的研究范围。     

Polymer grafted hydroxyapatite whisker as a filler for dental composite resin with enhanced physical and mechanical properties

The objective of this study was to investigate the effect of surface graft polymerization of hydroxyapatite whisker (HW) on physical and mechanical properties of dental composite resin. Poly bisphenol A glycidyl methacrylate (Poly(Bis-GMA)) was grafted onto silanized hydroxyapatite whisker (SHW) via solution polymerization and the amount of the Poly(Bis-GMA) on the surface was effectively controlled by polymerization time. The obtained poly(Bis-GMA) grafted hydroxyapatite whisker (PGHW) with different polymer contents was filled into a resin matrix respectively, meanwhile the composites with HW and with SHW served as controls. Monomer conversion was characterized by Fourier transform infrared spectroscopy (FTIR) and volume shrinkage of the composite resin was measured with a density tester. Mechanical properties were tested with a universal testing machine. The results indicated that the composite filled with PGHW-1 h (graft ratio of poly(Bis-GMA): 8.5 wt.%) showed lower shrinkage and better mechanical properties, improving flexural strength by 6.5% and 11.9% compared with SHW filled composite and HW filled composite, respectively. However, PGHW with higher graft ratios aggregated seriously and formed defects in the composite, leading to deterioration of mechanical properties. It was revealed that the poly(Bis-GMA) on the surface of PGHW acted as a functional transition layer and enhanced interfacial compatibility and interaction between whisker and resin matrix, which facilitated the dispersion of PGHW in the composite and decreased the composite shrinkage. Thus, the graft polymerization of Bis-GMA on the surface of filler might be a promising modification method for the fabrication of dental materials.     

On the heterogeneous structure of thermally cured bis-GMA/TEGDMA resins

In this paper we report on the morphogenesis of dental resins formed by a thermally initiated radical cross-linking copolymerization of model dental resins. These systems were considered reasonable model simplifications of the actual resins used in commercial filling composites, veneers, etc. Effect of bis-GMA content varying from 0 to 100% on the degree of conversion and morphology of the cured resin was investigated. Dynamic scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), dynamic mechanical thermal analysis (DMTA) and high temperature solvent extraction experiments were performed in order to determine the nature and location of unreacted unsaturations in relation to bis-GMA concentration. The interval of cure temperatures, ranging from 23 to 250°C, may seem irrelevant from the clinical point of view but is instrumental for an understanding of the processes involved. Single glass transition temperature (Tg) found in DMTA experiments showed that the copolymerization process between bis-GMA and TEGDMA is random in nature, however, the overall cure reaction is inhomogeneous and this inhomogeneity is increasing with increasing bis-GMA molar fraction. Heterogeneous character of the cure was reflected into the network morphogenesis characterized by microgellation preceded by cyclization and, following connection of microgels. These cure kinetics resulted in a heterogeneous morphology of the cured resin. Moreover, it was shown that the cure kinetics controls to a great extent the degree of conversion of the reactive vinylidene C=C bonds in a fully cured resin. A decrease in bis-GMA concentration in the resin mixture led to a higher degree of conversion, however, even a neat TEGDMA homopolymer did not exhibit C=C conversion greater than 65–70% under the cure conditions used. Leaching out tests, consisting of an extraction of unreacted monomer from a finely ground cured resin in boiling cyclohexanone at 160°C over a period of 5 d, revealed total weight loss of the order of 3.2–5.6 wt % regardless of the total conversion. No uncured monomer was detected in the extract solution using FTIR spectroscopy, however, the method used is not sensitive to the presence of oligomers. It was concluded that the remaining unreacted double bonds are the inevitable result of the diffusion controled heterogeneous cure reaction. The low rate of diffusion in the resin beyond its gel point is controlled by high monomer rigidity, low mobility and radius of gyration of the monomers. The unreacted C=C bonds exist in the form of pendant, side groups chemically attached to the network. In addition, a hypothesis has been proposed that for concentrations of rigid bis-GMA monomers above 50 wt %, preferably only one methacrylate group of its molecule has reacted on the time span of the experiment performed and has been incorporated in the cured network. Hence, a substantial part of unsaturation exists in the solid polymer in the form of pendant groups formed by mechanically ineffective bis-GMA monomers. The results are in good qualitative agreement with computer simulations based on the kinetic gelation model. © 2000 Kluwer Academic Publishers     

八氨苯基POSS交联改性聚氨酯弹性体的制备与性能

以八氨苯基多面体低聚倍半硅氧烷(OapPOSS)为交链剂,原位合成了含有POSS结构的聚氨酯弹性体纳米复合材料,分别采用FT-IR、光学显微镜,动态热机械(DMA)分析以及热重分析(TGA)等对所合成的复合材料进行了表征。结果表明:随着OapPOSS用量的增加,所制POSS/PUE复合材料的拉伸强度增加,扯断伸长率下降,储能模量增加,阻尼因子下降,玻璃化转变温度升高,热分解速率降低。     

新型聚多巴胺纳米颗粒光热蒸发性能评价

聚多巴胺具有与黑色素相似的吸光性能,是一种被广泛关注的高分子近红外吸收材料,在光热转化方面有良好前景。但由于其本身聚合机理多样,内部结构复杂,目前对聚多巴胺功能性设计的研究较少。本文通过设计Fe³⁺和硅烷偶联剂与多巴胺反应,提高了聚多巴胺的吸光特性和亲水性;通过X射线光电子能谱(XPS)、傅里叶变换红外光谱(FTIR)等表征证明,成功合成了高吸光度亲水聚多巴胺纳米颗粒,吸光度达到90%。同时将合成的纳米颗粒真空抽滤,堆叠构建亲水输运通道。实验表明：在太阳光蒸发环境,一个太阳光强下,使用本文设计的光热膜进行纯水蒸发实验,纯水蒸发速率可以达到1.1 kg/(m²·h),光热转化效率为80%,比普通聚多巴胺提高15%,证明该材料有很好的光热转化性能,在海水淡化领域有着良好的应用前景。     

累托石纳米晶层的高压剥离研究

首次采用物理方法高压制备了酚醛树脂(PF)/累托石(REC)粘土和酚醛树脂(PF)/有机改性累托石(OREC)粘土纳米复合材料,以X射线衍射(XRD)、透射电子显微镜(TEM)及红外光谱(IR)分析了复合材料的物相和显微结构。结果表明,不通过层间高分子聚合反应,在常温高压下,由聚合物分子插入粘土层间,可以形成剥离型树脂/粘土纳米复合材料。在100M Pa和500M Pa下,复合材料中的OREC完全剥离,而REC只有部分被剥离。     

静置水溶液聚合法合成AA/AM/AMPS高吸水性树脂

以N,N'-亚甲基双丙烯酰胺(NMBA)和聚乙烯醇(PVA)为复合交联剂,通过静置水溶液聚合法制备了丙烯酸(AA)/丙烯酰胺(AM)/2-丙烯酰胺基-2-甲基丙磺酸(AMPS)共聚高吸水性树脂.探讨了反应条件对树脂吸水性能的影响,并通过FT-IR、SEM等技术对树脂的分子结构及表面形态进行了表征分析.实验结果表明:优化条件下所合成的树脂最高吸蒸馏水倍率为1641倍.以NMBA和PVA为复合交联剂,可以优化树脂的交联网络结构,且PVA在树脂中具有双重作用.     

乳液聚合制备POSS/PVAc复合材料及其热性能

以1,3,5,7,9,11,13-苯基-15-乙烯基笼型倍半硅氧烷（乙烯基POSS）与醋酸乙烯酯（VAc）为原料,采用半连续乳液聚合法制备了POSS/PVAc复合材料。采用傅立叶转变红外光谱（FT-IR）、核磁共振（1H-NMR）等表征POSS/PVAc复合材料的结构和组成,利用X射线衍射（XRD）和透射电镜（TEM）...     

聚氨酯/环氧树脂互穿聚合物网络半硬泡沫的结构与性能

采用同步法合成了聚醚型聚氨酯/环氧树脂互穿聚合物网络半硬泡沫.通过FTIR,DMA,SEM研究了IPN半硬泡沫的化学结构、动态力学性能以及微观结构形态.FTIR分析表明了聚氨酯和环氧树脂的网络间存在接枝反应.很宽组成比范围内IPN半硬泡沫均显示出单一的宽温域玻璃化转变,而且该转变随着环氧树脂含量的增加向高温方向移动.通过SEM发现IPN半硬泡沫泡孔结构形状都比较均一.循环加载压缩发现所有IPN泡沫不仪压缩性能好而且具有很好的回弹性,大变形压缩后泡沫儿乎不变形,重复使用性能好.     

Development of a measuring system for on-line in situ monitoring of composite materials manufacturing

A unique portable measuring system using an impedance spectroscopy method with a self-adapting frequency of measurement is introduced. The system is intended for the on-line in situ monitoring of composite materials curing under industrial conditions. The capabilities of the developed system are demonstrated through the results obtained from on-line in situ measurements of unreinforced thermosetting resin, as well as of composites under real manufacturing conditions. Observations are supported by the results of other established methods for determining the degree of curing: temperature-modulated differential scanning calorimetry (MDSC), Fourier transform infrared spectroscopy (FT-IR) and broadband dielectric spectroscopy (BDS). Compressive and bending tests were also carried out on manufactured composites removed at different stages of the post-curing phase. Due to the self-adapting frequency, the system has enhanced sensitivity in the post-cure phase when the diffusion-controlled reactions proceed and, therefore, is suitable also for the analysis of hard post-cure samples.     

芳香族超支化聚酯型环氧树脂的合成及表征

以三羟甲基丙烷为中心核,与偏苯三酸酐和环氧氯丙烷开环聚合反应合成芳香族超支化聚酯,在碳酸钾水溶液作用下对其进行了闭环反应合成了超支化聚酯型环氧树脂。分别用红外光谱、核磁氢谱、凝胶色谱仪、热重分析表征了超支化聚酯型环氧树脂的结构。结果表明,合成产物具有芳香族超支化聚酯型环氧分子结构,合成的芳香族超支化聚酯型环氧树脂具有较好的热稳定性。