环氧基磁性离子交换树脂的合成与表征

用r—三氧化二铁—二乙烯三胺—双酚A环氧树脂首次合成了环氧基磁性离子交换树脂。实验结果表明,磁性树脂微球尺寸和吸附容量决定于树脂制备过程中的各种因素。一批典型的环氧基磁性树脂平均直径为0.15mm、吸附容量为3.3meq/g—R,磁化率为8.2emu/g—R,在酸性或碱性介质中稳定。实验数据也证实了这是一类优良的螯合树脂,对Zn~(2+)、Cd~(2+)、Hg~(2+)、Co~(2+)、Ni~(2+)、Pb~(2+)和其他二价阳离子有适当的螯合能力。但不吸附碱土金属离子,这和聚多胺树脂相同。     

球形纤维素磁性阴离子交换树脂的化学转化制备及特性研究

自制了大孔球形纤维素基阴离子交换树脂(PSC-AN),并利用化学转化法成功制备了大孔球形纤维素基磁性阴离子交换树脂(PSC-MAN)。对影响树脂质量磁化率的几个主要因素进行了探讨,实验确定最佳制备条件为:铁盐的配比为1∶10,EDTA的浓度为0.005 mol/L。对树脂的结构和性能进行了研究,表明化学转化法制备大孔球形纤维素基阴离子交换树脂(PSC-MAN)磁性强,在碱液中相当稳定,树脂磁化前后交换容量分别为Q前=1.33 meq/g、Q后=1.16 meq/g,即树脂基的交换容量基本不受磁化过程的影响。     

Merrifield树脂负载咪唑基离子液体磁性微球的制备与表征

制备了Merrifield树脂负载丙酸甲酯基咪唑基离子液体磁性微球。 采用FT-IR和XRD对结构进行了表征,采用TGA和VSM分别进行了热稳定性和磁性测试。 结果表明,丙酸甲酯基咪唑基离子液体成功负载到Merrifield树脂微球上,并通过共沉淀的方法实现了微球的磁性化,其磁组分为FeOOH和γ-Fe2O3混合物。 磁性微球的热稳定性优于无磁性的Merrifield树脂负载丙酸甲酯基咪唑基离子液体微球,在200 ℃以下不发生分解。 磁性微球的磁化强度为11.364 emu/g,显示出超顺磁性,无外磁场存在时不发生团聚。 沉降实验结果表明,在磁感应强度为3.0×10-4 T电磁场作用下,磁性微球10 s内即可从水相中基本分离完全,而没有磁场作用时磁性微球粒子基本不从水相中分离。     

纤维素基磁性聚偕胺肟树脂吸附锂

研究了氯化锂浓度、树脂含量和溶液的ＰＨ对碱式纤维素基磁性聚偕胺肟树脂吸附Ｌｉ＾＋离子能力的影响。在适当条件下，每个偕胺肟基可吸附两个Ｌｉ＾＋离子。     

聚苯乙烯磁性树脂的合成及性能

用悬浮聚合法,将γ—Fe_2O_3加入苯乙烯和二乙烯苯(DVB)中可制得聚苯乙烯磁性树脂。本文详细研究了各种因素对合成的影响。实验制得一批典型树脂的磁粉含量为12.8％,粒度为80目。磺化后得到磺酸型阳离子交换树脂,其交换容量为3.22mmol/g—R。实验表明,该种磁性树脂有一定的磁化性能,且耐碱性较好。     

磁性PS-DEA树脂的制备与表征

利用二乙醇胺(DEA)对氯甲基化聚苯乙烯基树脂(PS-Cl)进行表面改性,制备了亲水性的PS-DEA树脂,然后以FeCl3·6H2O和FeSO4·7H2O为前驱体通过共沉淀法原位复合制备了磁性PS-DEA树脂.表征了磁性PS-DEA样品的形貌、结构以及磁性能,研究了PS-DEA和磁性PS-DEA对水溶液中Hg(Ⅱ)的吸附性能.结果表明,含有Fe3O4的磁性PS-DEA树脂的比饱和磁化强度(Ms)为0.92 A·m2/kg,磁性树脂中Fe3O4所占的质量分数为1.7%.用Langmuir等温模型拟合了PS-DEA和磁性PS-DEA对水溶液中Hg(Ⅱ)的吸附数据,计算得到最大吸附量分别为320.51和352.11 mg/g,这表明磁性纳米粒子的引入有利于提高树脂的吸附性能,这种磁性树脂有望作为吸附剂用于水处理领域.     

化学转化法制备磁性阳离子交换树脂的研究

本文通过化学转化法即化学共沉淀法，分别研究了强酸性和弱酸性阳离子交换树脂的磁转化对相应所得树脂的磁性的影响，制得了磁性毫米级和微米级粒径的强酸性，弱酸性阳离子交换树脂。所得磁性树脂有磁性强，磁性物质分布均匀而且稳定，并保持树脂的原有特性。     

磁性阳离子交换树脂的结构与性能分析

利用古埃磁天平法、扫描电镜、粉末Ｘ射线衍射以及分光光度法等检测了化学转化法制备的磁性阳离子交换树脂。结果表明,所制备的树脂内部磁性物质为Ｆｅ３Ｏ４,且在 树脂内部的孔道及表面分布均匀,均被封锁在树脂内部,因而,这类磁性树脂在碱性和中性盐溶液中具有较高的稳定性。此外,树脂的磁化过程并不影响其交换容量。     

纤维素基磁性聚偕胺肟树脂的研究——溴在树脂上的氧化还原反应

用羟胺作模拟物与溴反应，测定了吸溴前后的酸式纤维素基磁性聚偕胺肟树脂的红外光谱，结合Ｆｒｅｕｎｄｌｉｃｈ及Ｌａｎｇｍｕｉｒ等温吸附方程的分析和吸溴前后树脂重量变化的测定，证明纤维素基磁性聚偕胺肟树脂吸溴后随即发生氧化还原反应，偕胺肟基被氧化为羧基，溴则被还原为溴离子，在溴浓度较高时，纤维素葡萄糖单元上的羟基被溴代或被氧化成羰酸，若葡萄糖苷键氧化断裂，将导致大分子降解。     

纤维素基磁性聚偕肟树脂的研究：—（NH4）2IrCl6在树脂上的咐吸

碱式纤维系基磁性聚偕胺肟树脂（ＢＭＡＯ）吸附（ＮＨ４）ＩｒＣｌ６是快速过程，属超当量吸附。吸附结果生成ＡＯ－Ｉｒ和ＡＯ２－Ｉｒ３络合物，随后Ｉｒ（Ⅳ）被偕胺肟基还原为Ｉｒ（０），聚集成球状晶簇随着在树脂表面。     

磁性珠状纤维素的性能表征

本文采用反相悬浮包埋技术制各了磁性珠状纤维素（magneticcellulosebead缩写MCB），并对MCB各方面的性能进行了全面的评价：湿态孔度高达80％以上，磁化率在10-3emu／g数量级，磁性铁分布均匀，且磁稳定性较高。     

Synthesis and characterization of novel phenolic resins containing aryl‐boron backbone and their utilization in polymeric composites with improved thermal and mechanical properties

In the present study, a novel aryl‐boron‐containing phenolic resin named as PBPR has been synthesized from phenol and formaldehyde in the presence of phenylboronic acid. The chemical structure of the PBPR was confirmed by Fourier transform infrared, nuclear magnetic resonance and X‐ray photoelectron spectroscopy. The molecular weight, viscosity and curing behavior were examined to demonstrate that PBPRs have better processability than common boric acid‐modified phenolic resin. The thermal stability and fracture toughness of the cured PBPRs were greatly enhanced, where the char yield at 1000°C (nitrogen atmosphere) and the glass transition temperature reached 70.0% and 218°C, respectively. The excellent mechanical and ablative properties of the PBPR composites may have benefited from the good interfacial adhesion between the resin matrix and the reinforced fiber. The flexural strength and the linear ablative rate are 436.8 ± 5.2 MPa and 0.010 mm/sec, respectively. This study opens a new window for the preparation of high‐performance ablative composites by designing a resin matrix containing an aryl‐boron backbone. Copyright © 2013 John Wiley & Sons, Ltd.     

Crystallization and reinforcement of poly (vinylidene fluoride) nanocomposites: Role of high molecular weight resin and carbon nanotubes

The effect of high molecular weight resin and multi-walled carbon nanotubes (MWCNTs) on the crystallization, rheological and dynamic mechanical properties of poly (vinylidene fluoride) (PVDF) composites was investigated. A synergetic effect of the high molecular weight resin and MWCNTs on the nucleation in the crystallization process of the matrix has been observed, and their contributions to the crystallization of the matrix are two-sided. The composites containing both the high molecular weight resin and MWCNTs have much higher crystallization peak temperatures but lower crystallinity, especially for samples with high MWCNT content. For the isothermal crystallization at relative high temperatures, higher Avrami exponent and shorter half-time of crystallization are observed for the composites containing both the high molecular weight resin and MWCNTs. The introduction of the high molecular weight resin not only reinforces the matrix, but also promotes the dispersion of MWCNTs. The reinforcement and synergetic nucleation effects of the high molecular weight resin and MWCNTs were also confirmed by dynamic mechanical analysis.     

Preparation and properties of graphene oxide nanosheets/cyanate ester resin composites

Graphene oxide nanosheets (GONSs)/cyanate ester (CE) resin composites were prepared via a solution intercalation method. The structures of the GONSs and the composites were studied using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The mechanical and tribological properties of the composites were investigated. In addition, the thermal behavior of the composites was characterized by thermogravimetric analysis (TGA). Results show that the GONSs/CE resin composites were successfully prepared. The addition of GONSs is beneficial to improve the mechanical and tribological properties of the composites. Moreover, the composites exhibit better thermal stability in comparison with the CE resin matrix.     

石墨烯改性树脂基复合材料力学性能研究进展

树脂基复合材料具有比强度高、比模量大、耐高温、耐腐蚀、质轻等诸多优点,在航天军工、生物医疗、电子封装、体育器材等众多领域得到广泛应用。石墨烯作为一种典型的二维纳米材料,凭借其独特结构以及优异的物理化学性能而备受关注。近年来的研究表明石墨烯可以通过对增强纤维改性和对基体树脂改性的方法来提高树脂基复合材料的力学性能。本文介绍了石墨烯改性树脂基复合材料的增强增韧机理,对石墨烯改性纤维(碳纤维、玻璃纤维、芳纶纤维)增强复合材料以及树脂的改性方法进行了综述;着重阐述了石墨烯改性树脂基复合材料力学性能的研究进展,分析了石墨烯改性树脂基复合材料研究中依旧存在的两大问题,即石墨烯的分散性和界面结合问题,并对石墨烯改性树脂基复合材料的未来发展前景进行了展望。     

New strategy to reinforce and toughen composites via introducing thorns-like micro/nanofibers

In this work, we report a new strategy of introducing thorns-like fiber into composites, so that the resultant composites substantially benefit from strong fiber–matrix interface adhesion. Specifically, the “thorns” could increase in interlocking molecules chains and entangle with the surrounding matrix resin, which could impede the mobility of polymer chains, as like the roots with uplift capacity. Strong interfacial adhesion between fibers and matrices is suggested by the SEM images and the DMA studies. After the thorns-like fibers are embedded into epoxy resin, the glass transition temperature (T_g) and the storage modulus (E′) are higher than these of neat epoxy and untreated fibers-reinforced epoxy, respectively, and the flexural properties of the composites reinforced with thorns-like fibers are significantly increased. Therefore these novel three dimensional thorns-like fibers will be applicable for composite materials based upon its unique architecture, making it an attractive alternative to increase the performance of any matrix resin.     

硫酸钙晶须改性双马来酰亚胺树脂摩擦磨损性能的研究

研究了载荷、偶联剂及硫酸钙晶须用量对双马来酰亚胺树脂摩擦磨损性能的影响及材料的磨损机制.结果表明,当摩擦载荷较大时,树脂基体在摩擦过程中出现明显的塑性变形和裂纹,而经过硫酸钙晶须改性的复合材料体系则塑性变形和裂纹情况得到明显的改善,并且磨损量显著降低.载荷从200 N增大到300 N后,树脂基体的磨损机制从粘着磨损过渡为严重的疲劳磨损,添加晶须体系仍以粘着磨损为主.晶须添加量较小时,复合材料的磨损机理主要为粘着磨损,晶须添加量较高时,磨粒磨损占主导地位.     

Study of the thermal properties of polyester composites loaded with oriented carbon nanofibers using the front-face flash method

In this work, we have prepared polyester resin based composites, loaded with carbon nanofibers decorated with magnetite nanoparticles (m-CNF) in several volumetric concentrations covering from 0 to 3.25% and oriented applying a constant magnetic field before polymerization. A study of the heat transfer along the direction of the alignment of the fibers was performed by measuring the in-depth thermal diffusivity and thermal effusivity using the laser flash method in the front-face configuration. For the maximum volumetric concentration of aligned nanofibers along the thickness of the sample, an improvement of 80% of the thermal conductivity above the thermal conductivity of the polyester resin was observed. In contrast, the increment of the thermal conductivity was only of 20% above the value of the matrix for samples with non-oriented carbon nanofibers. The effects of the m-CNF and their orientation on the effective thermal conductivity of the composites were analyzed using a simple theoretical model, which takes into account the thermal mismatch between the matrix and the fillers, as well as the aspect ratio of the embedded fibers.