聚酰亚胺／SiO2杂化材料的硅核磁共振波谱和电光性质的研究

以含氟的二胺5，5’-（六氟异丙基）-二-（2-氨基苯酚）（6FHP）及二酐4，4’-（六氟异丙基）-苯二酸酐（6FDA）或均苯四甲酸酐（PMDA）为单体，以分散红1（DR1）为活性生色分子合成具有非线性光学特性的含氟聚酰亚胺，并采用溶胶-凝胶（Sol—Gel）法合成相应的聚酰亚胺／SiO2杂化材料。采用固态^29SiMASNMR谱研究了含氟聚酰亚胺／SiO2杂化材料的交联结构，结果表明杂化材料中是以T^3、Q^3、Q^4结构为主，说明在杂化材料中形成了交联网状结构．采用衰减全反射（ATR）测定了聚酰亚胺和杂化材料在832nm处的电光系数，其值分别为32、28、34和29pm／V，结果表明具有较高的电光系数。     

聚苯乙烯/二氧化硅杂化材料的原位制备

采用活性负离子聚合法和末端官能化改性技术合成三乙氧基封端聚苯乙烯,然后用溶胶-凝胶法合成聚苯乙烯(PS)/SiO2杂化材料,用红外光谱、凝胶渗透色谱、差示扫描量热法、热重分析、扫描电子显微镜对PS/SiO2杂化材料的结构和性能进行分析。结果表明:PS/SiO2杂化材料中的PS和SiO2间有化学键相连;PS/SiO2杂化材料中的w(SiO2)为25%时,SiO2是粒径约为180 nm,且粒径分布均匀、有完善球形结构的颗粒,其玻璃化转变温度比纯PS高1.3℃,热稳定性较纯PS高。     

溶胶-凝胶法聚丙烯酸丁酯/二氧化硅杂化材料弹性体的制备与表征

用丙烯酸丁酯与少量功能单体共聚,合成了分子链侧基带羟基的聚丙烯酸丁酯(PBA)乳液,然后与硅溶胶混合,用溶胶-凝胶法制备了PBA/SiO2杂化材料弹性体;研究了SiO2含量对杂化材料弹性体力学性能及透光率的影响,并用扫描电子显微镜、傅里叶变换红外光谱、差示扫描量热分析和动态力学性能分析对杂化材料弹性体的结构进行了表征。结果表明,PBA/SiO2杂化材料热压后成为一种力学性能优良的具有一定透光率的弹性体。随着SiO2含量的增加,杂化材料弹性体的力学性能提高,透光率和SiO2粒子的粒径增加,PBA基体的玻璃化转变温度和损耗因子下降;PBA共聚物分子链侧基所带羟基与SiO2粒子表面的硅醇基发生了缩合脱水反应,形成了Si—O—C共价键,使PBA基体与SiO2粒子构成的界面结合紧密,从而赋予杂化材料弹性体以优良的性能。     

有机-无机杂化介孔氧化硅凝胶材料的高效合成

同时采用正硅酸乙酯(tetraethylorthosilicate,TEOS)和甲基含氢硅烷[poly(methylhydrogen)siloxane,PMHS]作为反应组分[保持质量比m(TEOS)/m(PMHS)=6],通过溶胶-凝胶合成路线制备有机-无机杂化的介孔氧化硅凝胶材料。借助固体硅核磁共振、扫描电子显微镜、高分辨透射电子显微镜、低温氮气吸附/脱附、热分析和Fourier红外光谱等测试手段对杂化凝胶材料进行系统表征。分析结果表明:甲基化凝胶材料呈现"蠕虫状"孔道结构特征,孔径分布均匀,比表面积和孔体积分别为780m2/g和0.64cm3/g。     

PU/SiO2杂化材料的制备与表征

用溶胶-凝胶法制备了一系列聚氨酯(PU)／SiO2杂化材料,通过扫描电子显微镜和傅里叶变换红外光谱考察了杂化材料的相容性、微观相互作用以及介电性能。实验发现．水和催化剂的用量控制得当可得到分散均匀的杂化材料;在10μm厚的聚对苯二甲酸乙二酯(PET)薄膜上涂有2μm厚的PU／SiO2杂化材料,体系的介电常数较纯PET薄膜提高1倍多。     

SiO_2杂化改性CPVC树脂的制备与表征

以γ-氨丙基三乙氧基硅烷(KH550)和正硅酸乙酯(TEOS)为SiO_2前躯体,利用KH550和TEOS的原位溶胶-凝胶反应,制备SiO_2杂化改性氯化聚氯乙烯(CPVC)树脂。采用傅里叶变换红外光谱仪(FTIR)、X射线能谱仪(EDS)以及扫描电子显微镜(SEM)表征了改性CPVC的化学结构和微观形貌;并采用热失重分析仪(TGA)和差示扫描量热仪(DSC)对改性前后树脂的热性能进行了分析。结果表明:SiO_2与CPVC发生了杂化,且杂化后树脂的粒径减小;改性后CPVC树脂的耐热性能得到显著提高,分子链运动受到杂化网络限制,玻璃化转变温度和熔点均有所提高。     

水含量对PI/SiO2纳米杂化薄膜热稳定性的影响

以TEOS为无机前躯体,采用溶胶-凝胶路线成功制备了水含量不同的3种聚酰亚胺/二氧化硅(P1/SiO2)纳米杂化薄膜.采用傅立叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)、热重分析(TGA)等方法研究了杂化薄膜的结构与热稳定性.研究结果表明:水含量对PI/SiO2杂化薄膜热稳定性影响很大.在水含量不同的3种杂化薄膜中,当水含量为1:6时,热稳定性最高.在质量损失为5％时,杂化薄膜的热分解温度为592.1℃.与纯PI相比,热稳定性升高.     

PI/T-SiO2杂化薄膜的制备及偶联剂的影响

利用模板法制备了纳米管状SiO2(T—SiO2),在此基础上合成了聚酰亚胺(T-SiO2杂化薄膜。采用透射电子显微镜和扫描电子显微镜对T—SiO2的形态进行了研究,用红外光谱分析了硅烷偶联剂对杂化薄膜微观结构的影响,并讨论了偶联剂加入方式、用量等因素对杂化薄膜力学性能的影响。结果表明,所制备的SiO2主要为管口直径分布在100-500nm,长径比在10～500的T—SiO2;在聚酰胺酸形成后,加入经偶联剂改性的T—SiO2,且偶联剂用量为填料质量的10％时,杂化薄膜的拉伸强度和弹性模量取得最佳值,分别为111．8MPa和1．42GPa。     

聚丁二烯/烯丙基异丁基多面体低聚倍半硅氧烷纳米杂化材料的形貌及性能

对采用活性负离子聚合法制得的聚丁二烯( PB)/烯丙基异丁基多面体低聚倍半硅氧烷(A - POSS)纳米杂化材料进行硫化,采用X射线衍射仪、扫描电子显微镜、差示扫描量热法、热重分析、动态力学性能分析等手段,研究了A - POSS含量对硫化PB/A -POSS纳米杂化材料的微观形貌、耐热性能和动态力学性能的影响.结果表明...     

含氟PET的非等温结晶动力学

通过分子设计,在聚对苯二甲酸乙二酯(PET)大分子主链上同时引入耐热性的芳杂酰亚胺环和含氟基团。以六氟二酐和氨基十一酸为原料,通过热环化反应合成酰亚胺二酸,再用制备的酰亚胺二酸单体按照不同配比和对苯二甲酸二甲酯、乙二醇按一定比例调节投料比进行酯化缩聚反应,合成一系列含氟PET。利用差示扫描量热(DSC)法研究了聚合物非等温结晶行为,发现纯PET的结晶能力最强,随着含氟量的增加,结晶能力减弱。采用Jeziorny法分析了纯PET和含氟PET的非等温结晶动力学,发现结晶速率常数随着含氟链段的加入而减小,表明含氟链段的加入降低了PET的结晶能力。     

交联聚酰亚胺的减摩增韧改性

采用短碳纤维（ＣＦ）、聚四氟乙烯（ＰＴＦＥ）和缩合型线性聚酰亚胺（ＣＰＩ），用机械共混、热压模塑的方法，对加成型交联聚酰亚胺（ＡＰＩ）进行减摩增韧性性，并对复合材料的摩擦磨损、力学性能和形态结构进行了测试与分析。研究结果表明，与纯ＡＰＩ相比，含１０％ＣＦ的ＡＰＩ复合材料的冲击强度提高了２８０％；含２０％ＣＰＩ的ＡＰＩ复合材料的冲击强度，弯曲强度分别提高了１５０％和６０％；含３０ＴＰＴＥＥ的ＡＰＩ复     

Thermal and anti‐corrosion analysis of nano‐porous phenolic‐novolac‐Zn composite materials

The phenolic‐novolac‐Zinc composite materials with hexamethylenetramine (HMTA) 8 wt% at Zinc powder content weight from 2% to 11% are investigated by Scanning Electron Microscope, Differential Scanning Calorimetry, Thermogravimetric analysis, and Kissinger method. It is found that a nano‐porous structure is synthesized in phenolic‐novolac porous with 8 wt% HMTA and 5 wt% Zn powder. The thermal and anti‐corrosion analysis shows that the composite with nano‐pores structure produces the highest glass‐transtion temperature, decomposition temperature, and the best anti‐corrosion property comparing with other samples. Furthermore, it introduces a novel method to prepare the nano‐porous phenolic‐novolac‐Zn composite material which can be used as the functional material. POLYM. COMPOS., 36:1346–1351, 2015. © 2014 Society of Plastics Engineers     

Soy Oil-Based Rigid Polyurethane Biofoams Obtained by a Facile One-Pot Process and Reinforced with Hydroxyl-Functionalized Multiwalled Carbon Nanotube

Highly conductive, thermally insulating, and three-dimensional (3D) macromolecular network-structured nanocomposite biofoams with very low density were designed from soy oil-based polyurethane (PU) and hydroxyl-functionalized multiwalled carbon nanotubes (MWCNT-OH) using a facile one-pot process with water as the sole blowing agent. Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and Fourier Transform Infrared spectroscopy (FTIR) analyses revealed homogeneous dispersion as well as interaction or reaction of MWCNT-OH with the PU biofoam matrix or a polymeric methylene diphenyl diisocyanate (MDI) to form a 3D macromolecular network structure. Mechanical properties and electrical conductivity were remarkably enhanced with the increase of MWCNT-OH. Dynamic mechanical analysis and thermogravimetric analysis results showed that all the nanocomposite PU biofoam products had good thermal stability properties. Hence, the prepared nanocomposites hold promise as rigid biopolyurethane (BioPU) foams, serving the needs of the conductive composite material fields.     

Synthesis and Characterization of Thiophen-3-yl Acetic Acid 4-Pyrrol-1-yl Phenyl Ester and its Conducting Polymers

ABSTRACT

Thiophen-3-yl acetic acid 4-pyrrol-1-yl phenyl ester (TAPE) monomer was synthesized via reaction of thiophen-3-yl acetyl chloride with 4-pyrrol-1-yl phenol. Homopolymers were achieved by using electrochemical and chemical polymerization techniques. Copolymers of TAPE with bithiophene or pyrrole were synthesized by potentiostatic electrochemical polymerization in acetonitrile-tetrabutylammonium tetrafluoroborate (TBAFB) solvent-electrolyte couple. The chemical structures were confirmed by both Nuclear Magnetic Resonance Spectroscopy (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Differential Scanning Calorimetry (DSC) and Thermal Gravimetry Analysis (TGA) were used to examine the thermal behavior of the polymers. The morphologies of the films were investigated by Scanning Electron Microscope (SEM). Two-probe technique was used to measure the conductivities of the samples. Moreover, investigations of electrochromic and spectroelectrochemical properties of poly(TAPE-co-BiTh) carried out and the characteristics of dual type electrochromic device based on poly(TAPE-co-BiTh) and poly(3,4-ethylenedioxythiophene) (PEDOT) were reported.     

双组分水性聚氨酯涂膜交联密度的研究

通过耐溶剂擦拭实验、溶胀率实验、盖尔分率实验、红外光谱、扫描电子显微镜(SEM)和差示扫描量热仪(DSC)测试等方法研究了不同玻璃化温度(Tg)的羟基组分、n(—NCO)∶n(—OH)及不同固化时间对双组分水性聚氨酯涂膜交联密度的影响。结果表明:羟基组分的Tg对涂膜的交联密度有较大影响,Tg为22℃的羟基丙烯酸分散体和水性HDI基固化剂交联的涂膜具有最大的交联密度;水性双组分聚氨酯涂膜在25℃条件下干燥7 d可达到最大的耐溶剂擦拭次数,异氰酸酯固化剂和羟基分散体的n(—NCO)∶n(—OH)值为1.5~2.0时制得的涂膜有较好的交联密度。     

Antireflective coatings using organically modified silica and polyimide via solution casting method

Antireflective (AR) coatings were prepared using a polyimide and two types of organically modified silica colloids via a solution casting method. The optically transparent polyimide was prepared from 2,2′‐Bis[4‐(3,4‐dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) and 4,4′‐oxydianiline (ODA). The silica colloids were driven to the coating‐air interface by either the fluorinated alkyl group or PDMS (Polydimethylsiloxane) segment tethered onto the silica colloids. The amount of fluorinated alkyl groups and the molecular weight of the siloxane grafted on the silica colloid were varied. The PDMS‐silica and fluorosilica colloids were characterized by TEM (Transmission Electron Microscopy), DLS (Dynamic Light Scattering), FTIR (Fourier Transform Infrared Spectroscopy), solid‐state ¹³C NMR (Nuclear Magnetic Resonance) and solid‐state ²⁹Si NMR. The AR coatings were characterized by UV–vis (Ultraviolet–Visible Spectroscopy) transmittance spectra, AFM (Atomic Force Microscope), and SEM (Scanning Electron Microscope). The effects of modified silica loading and type of solvent on AR properties were studied. An enhancement in AR activity was observed for 1 wt% PDMS‐modified (low molecular weight) silica coatings and 3 wt.% fluorosilica‐10 in dimethylacetamide (DMAc). In comparison with cyclopentanone (CPT), DMAc favors migration of silica particles toward coating‐air interface giving higher transmittance. The migration of particles to the surface and consequently increased surface roughness was observed by SEM. POLYM. ENG. SCI., 53:2228–2241, 2013. © 2013 Society of Plastics Engineers     

Synthesis and characterization of new thermosetting polybenzoxazines with other functional groups in the network

In this work, novel thermosetting systems of high performance based on multi-functional benzoxazines were developed. First, 3-(2-hydroxyethyl)-3,4-dihydro-2H-1,3-benzoxazine (BzOH) and bis(3-(2-hydroxyethyl)-3,4-dihydro-2H-1,3- benzoxazinyl) isopropane (BzPOH) monomers were synthesized by reaction between phenol or bisphenol A, paraformaldehyde, and ethanolamine. Then, BzOH and BzPOH were functionalized with maleic anhydride using a stoichiometric ratio of oxazine: maleic anhydride (1:1) to produce low molar mass species with carboxylic acid groups, named BzFA and BzPFA. The products were characterized by Nuclear Magnetic Resonance (NMR), Size-Exclusion Chromatography (SEC), and Fourier Transform Infrared Spectroscopy (FTIR). BzFA and BzPFA exhibited weight-average molecular weights of 5000 g.mol^?1and 50,000 g.mol^?1, respectively. Mixtures between the new precursors and the conventional benzoxazine (BzBA) derived from bisphenol A and aniline [bis(3-phenyl-3,4-dihydro-2H-1,3benzoxazinyl) isopropane] were prepared. The curing process was studied by FTIR and Differential Scanning Calorimetry (DSC), and viscoelastic, mechanical, thermal, and morphological properties of the materials were also evaluated. Materials obtained exhibited better thermal, viscoelastic and mechanical properties than conventional polybenzoxazine. Scanning Electron Microscope (SEM) measurements indicated homogeneous material surfaces.     

Preparation and Properties of 2,6‐Diamino‐3,5‐dinitropyrazine‐1‐oxide based Nanocomposites

With estane as binder, a new nanocomposite energetic material based on 2,6‐diamino‐3,5‐dinitropyrazine‐1‐oxide (LLM‐105) was successfully prepared by the spray drying method. Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and X‐ray diffraction (XRD) was employed to characterize the nanocomposite samples. The impact sensitivity and thermal decomposition properties of the nanocomposites were also measured and analyzed. The results show that the nanocomposite particles are spherical in shape and range from 1 μm to 10 μm in size. The composite is aggregated of many tiny granules with nucleus/shell structure, in which the shell thickness and crystal size of LLM‐105 are about 20 nm and 50–100 nm. The crystal type of LLM‐105 in the nanocomposite is similar to that of raw LLM‐105, however, the diffraction peaks become weaker and wider mainly due to decreasing of particle size. The nanocomposite has lower impact sensitivity and better thermal stability.     

Preparation and characterization of magnetic polyimide hybrid thin films

Magnetic polyimide hybrid thin films were synthesized from pyromellitic dianhydride (PMDA), 4,4′-oxydianiline (ODA), and Fe₃O₄ magnetic nanoparticles via thermal imidiazation in nitrogen environments. The magnetic polyimide hybrid thin films were analyzed and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The magnetic properties of magnetic nanoparticles and polymer hybrid thin films were assessed using a vibrating sample magnetometer (VSM), and the physical properties of hybrid thin films were tested. Results revealed that the magnetic polyimide hybrid thin films had superparamagnetic behavior and excellent mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012