Bio-Based Hyperbranched Toughener From Tannic Acid and Its Enhanced Solvent-Free Epoxy Resin with High Performance

It is essential to design economic and efficient tougheners to prepare high-performance epoxy resin;however,this has remained a huge challenge.Herein,an eco-friendly,low-cost,and facile-fabricated bio-based hyperbranched toughener,carboxylic acid-functionalized tannic acid(CATA),was successfully prepared and applicated to the preparation of solvent-free epoxy resins.The mechanical performance,morphology,structural characterization,and thermal characterization of toughened epoxy resin system were studied.The toughened epoxy resin system with only 1.0wt%CATA reached the highest impact strength,111%higher than the neat epoxy resin system.Notably,the tensile strength and elongation at break of toughened epoxy resin systems increased moderately with increasing CATA loading.Nonphase-separated hybrids with significant toughening effect were obtained.Additionally,the thermal stabilities of toughened epoxy resin systems decreased with increasing CATA loading.This study provides an eco-friendly,cost-effective,and facile approach for the preparation of high-performance,solvent-free epoxy resins with potential for practical applications in sealing integrated circuits and electrical devices fields.

Preparation of carbon brushes with thermosetting resin binder

Carbon brushes with a resin binder were prepared according to an industrial process and the effects of the molding pressure, grains size and cure temperature on the properties of brush samples were discussed. The results show that the bulk density, bending strength and Rockwell hardness increase, while resistivity decreases with increasing molding pressure. Cure temperature has much more influence on the properties of brushes than molding pressure and grains size. Isothermal differential scanning calorimetry(DSC) was used to estimate the degree of cure of resin binder and a novel method of using the true density to measure the degree of cure of resin binder was presented and discussed briefly. Based on optimal process parameters carbon brushes were manufactured, durability tests for brushes were carried out on an alternate current motor and scanning electron microscope(SEM) was adopted to observe the morphology of worn surface of brushes. The results show that a luster oxide film can be formed on the surface of brushes and their service life reaches 380 h.

Facile Synthesis of a Novel Bio-Based P-N Containing Flame Retardant for Effectively Reducing the Fire Hazards of Epoxy Resin

In this work,a bio-based flame retardant(Cy-HEDP)was synthesized from cytosine and HEDP through a facile salt-forming reaction and embedded into epoxy matrix to improve the flame retardancy and smoke suppression performance.The product Cy-HEDP was well characterized by FTIR,^(1)H and^(31)P NMR and SEM tests.On the basis of the results,by adding 15 wt%Cy-HEDP,the EP15 can pass UL-94 V-0 rating,and the total smoke production(TSP)as well as total heat release(THR)can be decreased by 61.05%(from 22.61 to 8.7 m^(2)/m^(2))and 39.44%(from 103.19 to 62.50 MJ/m^(2))in comparison to the unfilled EP,reflecting the attenuated smoke toxicity and impeded heat generation.According to the analysis results of residual char,it can be concluded that Cy-HEDP possessed the ability to promote the formation of continuous and dense char layers,which would be a physical barrier to insulate oxygen and prevent heat feedback during the combustion of EP.This work provide inspiration towards developing bio-based flame retardant,probably extending the prospects to other polymeric material system.

Recyclable bio-based epoxy resin thermoset polymer from wood for circular economy

Due to their extraordinary durability and thermal stability,Epoxy Resin Thermosets(ERTs)are essential in various industries.However,their poor recyclability leads to unacceptable environmental pollution.In this study,Wu et al.successfully synthesized a completely bio-based ERT using lignocellulose-derived building blocks which exhibit outstanding thermal and mechanical properties.Remarkably,these bio-materials degrade via methanolysis without the need of any catalyst,presenting a smart and cost-effective recycling strategy.Furthermore,this approach could be employed for fabricating reusable composites comprising glass fiber and plant fiber,thereby expanding its applications in sustainable transportation,coatings,paints or biomedical devices.

Unleashing the Power of Bio-based Thermotropic Liquid Crystal Modifiers:Toughening and Reinforcing Petroleum-based Epoxy Resin without Compromising Other Properties

Toughening the petroleum-based epoxy resin blends with bio-based modifiers without compromising their modulus,mechanical strength,and other properties is still a big challenge in view of the sustainability.In this study,a bio-based liquid crystal epoxy resin(THMT-E P)with an s-triazine ring structure was utilized to modify a petroleum-based bisphenol A epoxy resin(E51)with 4,4'-diaminodiphenylsulfone(DDS)as a curing agent,and the blended systems were evaluated for their thermal stability,mechanical properties,and flame retardancy.The results showed that the impact strength of the blended system initially increased and then decreased with the increase in THMT-EP content,and it reached the a maximum value of 26.5 kJ/m^(2)when the THMT-EP content was 5%,which was 31.2%higher than that of E51/DDS.Notably,the flexural strength,modulus,and glass transition tem perature of the blended system were all simultaneously improved with the addition of THMT-EP.At the same time,the addition of THMT-EP enhanced the flame retardancy of the system by increasing the char yield at 700℃and decreasing the peak heat release rate and total heat release rate.This work paves the way for a more sustainable improvement in the comprehensive performance of epoxy resin.

PREPARATION AND PROPERTIES OF THERMOSETTING ACRYLIC COATINGS USING TITANIUM-OXO-CLUSTER AS A CURING AGENT

Thermosetting acrylic coatings were prepared by using carboxyl acid group-containing acrylic oligomer and curing with titanium-oxo-clusters which were first pre-hydrolyzed from titanium n-butoxide.The curing ability of the titanium-oxo-cluster was examined using a microdielectric analytical(DEA)curing monitor,Fourier transformed infrared spectroscopy(FTIR),and Soxhlet extraction experiments,and the properties of the resulted coatings were investigated with pendulum hardness tester,dynamic mechanical analysis(DMA),thermogravimetric analysis(TGA)and ultraviolet-visible spectrometer.The effect of titania-oxo-cluster in leading acrylic oligomers to form thermosetting acrylic coatings was confirmed.An increasing pendulum hardness and modulus of acrylic coatings with increasing titania content was observed, which resulted from the increment of crosslinking degree rather than of the titania content.The thermosetting acrylic/titania coatings also showed better thermal stability and higher UV-blocking properties than those coatings using organic curing agent.

Bio-Based Polymers for Technical Applications: A Review — Part 2

Triglyceride oil of plant seed cannot be used on its own without further modification. The fatty acids must be suitably functionalized in order to add polymerisable functionalities which will help in the curing process. The purpose of these modifications is to reach a higher level of molecular weight and cross-link density, and also to incorporate chemical functionalities known to impart stiffness in a polymer network. The modification can go through various path ways which were described in this study.

Flame Retardants Nanocomposites-Synergistic Effect of Combination Conventional Retardants with Nanofillers of the Flammability of Thermoset Resins

The consumption ofthermoset resins as building polymers is approximately over one million tone word wide. The thermoset resins are proven construction materials for the technical and highly demanding applications of the transportation, electrical and building part industry. Heat stability, high thermal, low shrinkage, excellent mechanical properties are typical for their type of polymers. Above applications in addition to the mechanical properties also require good flame retardants of the materials. Undertaken activities refer to official draft, laws and legal recommendations in UE states. This paper presents positive effect of reduced flammability of thermoset resins （unsaturated polyester and epoxy resins） thanks to the use of nanocomposites containing multi-ingredient halogen-flee flame retardants which combine conventional phosphorus/nitrogen modifiers interacting with nanofillers （oMMT （organomodified montmorillonite）, EG （expandable graphite）, graphene, GO （graphene oxide）, nSi （nanosilica））.

基于香草醛的热固性树脂研究进展

香草醛是一种可由木质素磺酸盐生产的单芳香化合物,其化学结构独特,已成为生物基材料领域研究热点。本文首先介绍了基于香草醛的热固性高分子材料包括环氧树脂、苯并噁嗪、酚醛树脂、丙烯酸树脂等研究进展,着重论述了基于香草醛特征结构进行化学转化以及制备交联结构产物的过程。进而,本文总结了含有动态共价键的香草醛基热固性材料研究进展。香草醛的醛基有利于缩醛、亚胺、硫缩醛等动态化学基团的引入,而通过交联体系的选择可有效引入动态二硫键、D-A加成键及β-羟基酯基团。在总结香草醛基热固性材料的特点及发展应用的基础上,本文展望了香草醛基热固性树脂在原料获取、产品制备、回收利用及有效降解等方面可持续性所面临的挑战。

纤维增强热固性树脂基复合材料成型过程数值模拟研究进展

纤维增强热固性树脂基复合材料在高端制造领域应用广泛,其固化过程涉及树脂流动、固化反应发生、残余应力引发固化变形等多个步骤。数值模拟纤维增强热固性树脂基复合材料的工艺成型过程是一个多场耦合的复杂问题,建立完善的数值模拟方法用来预测其成型过程中的固化行为对于工艺类型选择、工艺参数设计和复合材料构件性能优化具有重要的理论与实践意义。本文归纳了数值模拟纤维增强热固性树脂基复合材料成型过程的主要研究进展,并讨论了不同数值模型的适用条件,通过分析同一问题不同模型的适用条件可以为复合材料固化工艺及参数设计的选择提供指导。提升精度和降低成本是数值模型迭代优化的主要研究方向。在此基础上,本文对数值模拟纤维增强热固性树脂基复合材料成型过程进行了总结,并认为未来可以从复合材料的树脂流动多尺度建模、机器学习与材料基因组方法在复合材料的构件优化设计中的应用和残余应力对复合材料的性能及使用寿命的影响等方面开展研究。

可回收热固性环氧树脂及其玻纤增强复合材料性能研究

为了研究可回收环氧树脂R与风电叶片中常规环氧灌注树脂的区别,采用真空灌注工艺制备了玻璃纤维增强可回收热固性复合材料,对比分析了树脂之间的材料性能以及其复合材料之间的力学性能。结果表明,可回收树脂R的粘度与常规灌注树脂相近,适用期长于常规灌注树脂,适用于风电叶片的真空灌注工艺;放热峰出现时间略早于常规灌注树脂,有利于减少生产工时;其本体性能、复合材料力学性能与常规灌注树脂大体相当;可回收树脂R与常规灌注树脂的之间具有良好的界面性能,表明该树脂可以通过先制备部件然后整体灌注成型的方式制造大型复合材料制件。

碳纤维增强树脂基复合材料界面改性及应用进展

轻质高强的碳纤维增强树脂基复合材料(CFRP)在碳达峰和碳中和的国家战略中展现出重要的研究价值,提高复合材料界面结合强度是重点和难点问题。针对碳纤维表面浸润性差和力学性能转化率低的问题,简述了CFRP界面增强理论和碳纤维表面处理方法,重点阐述了氧化法、化学接枝和涂层法,用物理或化学手段提高复合材料力学性能。此外,从热固性树脂和热塑性树脂两种基体材料的各自性能特点分析了碳纤维与树脂基体适配性的问题,提出了不同的解决方案。最后,介绍了CFRP在航空、风电叶片和新能源汽车领域的研究进展,提出了飞机轻量化、风机大型化和电车普及背景下材料研究的发展建议,如优化针对高强或高模等具有不同表面形态碳纤维的特定表面改性技术,开发针对不同树脂的改性方法,研发不同类别及应用场景下的碳纤维上浆剂,加强复合材料界面增强理论和界面表征技术研究,制定碳纤维复合材料标准化体系。

热固性树脂基复合材料在表面防护领域的研究现状

热固性树脂因其固化后不溶不融、硬度高、比刚性大、耐高温且成品具有优异的尺寸稳定性,在防护涂料、轨道交通、航空航天等广大应用领域获得了认可。然而,随着材料技术的高速发展,传统热固性树脂的力学性能已难以满足各行各业选用材料的性能要求。针对此类问题,目前的解决方案主要围绕新型热固性树脂的研发和对传统热固性树脂进行改性两方面。改性后的热固性树脂综合性能得到了显著提升,且制备周期较短,在抗烧蚀、耐磨损和耐腐蚀等领域起着至关重要的作用。本文综述了近年来热固性树脂基复合材料在抗烧蚀、耐磨损和耐腐蚀等表面防护领域的研究现状,并对其材料种类、防护机理及环境对其性能的影响进行了梳理和总结,探讨了热固性树脂基复合材料未来的发展方向,可为其在接下来的研究中提供理论和技术参考。

Thermosetting resin modified asphalt:A comprehensive review

Thermosetting resins have advantages such as high strength,corrosion resistance,and aging resistance,and have excellent prospects for practical application as asphalt modifiers.In order to promote the research of thermosetting resin modified asphalt,to provide direction for its further research,this paper reviews the research progress of thermosetting resin modified asphalt in recent years.The material composition,modification mechanism,and curing behavior of epoxy asphalt,thermosetting polyurethane modified asphalt,unsaturated polyester modified asphalt,and other thermosetting resin modified asphalts are overviewed.Different types of thermosetting resin modified asphalt have different performances,the performance advantages of different thermosetting resin modified asphalts are summarized.At the same time,the existing problems in thermosetting resin modified asphalt and further research directions are provided.Encouraging researchers to produce thermosetting resin modified asphalts using waste or bio-based materials,and to study the recycling technologies and life cycle assessment of thermosetting resin modified asphalt.This paper provides a reference for the study of thermosetting resin modified asphalt.

动态共价热固性树脂及复合材料的研究进展

纤维增强热固性树脂基复合材料具有高比强度、高比模量、耐热性好等优点,在航空航天等重要领域应用广泛。然而,其存在成型后无法重复加工以及材料回收处理困难的问题。通过将动态共价键引入交联树脂体系,可以制备得到动态共价热固性树脂,这类树脂具有可回收、可重塑等类似热塑性聚合物的动态性能,为解决上述问题提供了一种有效途径。本文介绍了动态共价热固性树脂的发展历程、基本特征及网络调控策略,简述了以其为基体的纤维增强复合材料基本特点,随后以动态共价键类型进行分类标准,综述了酯交换型、双硫交换型、亚胺交换型及其他键交换型热固性树脂及其纤维增强复合材料的研究进展,并概述了这类复合材料的发展趋势及商业化应用。最后总结了上述树脂及复合材料的未来发展方向并提出设计建议,为该材料的设计开发及商业化应用提供思路。

可降解热固性树脂研究进展

传统的热固性树脂因不可逆的交联网络结构而不溶、不熔,导致其难以降解回收,造成环境污染及资源浪费。通过分子设计,将可裂解键或动态共价键引入到热固性树脂的交联网络,在一定的降解条件可实现传统热固性树脂的可控降解是解决上述问题的有效途径之一。介绍了传统热固性树脂回收利用面临的问题,综述了不同类型可降解热固性树脂的降解机理、制备方法及可回收性,最后指出目前可降解热固性树脂存在的问题,并对未来重点的研究方向进行展望。

碳纳米管改性热固性树脂的研究进展

随着科技的进步,碳纳米管因其独特的性能,在材料科学领域引起了广泛的研究关注。碳纳米管是一种性能优异的一维量子材料,有良好的导电特性、力学特性和导热特性;热固性树脂是一种高分子聚合物材料,其分子链通过化学交联能形成坚固的三维网络结构,有出众的耐老化、抗腐蚀、耐热等特点。从力学性能、耐热性能、导电性能和电磁性能四方面总结了碳纳米管改性热固性树脂的研究进展,也为下一步的研究提供了方向。

Electrospun porous carbon nanofibers derived from bio-based phenolic resins as free-standing electrodes for high-performance supercapacitors

Phenolic resins were employed to prepare electrospun porous carbon nanofibers with a high specific surface area as free-standing electrodes for high-performance supercapacitors.However,the sustainable development of conventional phenolic resin has been challenged by petroleum-based phenol and formaldehyde.Lignin with abundant phenolic hydroxyl groups is the main non-petroleum resource that can provide renewable aromatic compounds.Hence,lignin,phenol,and furfural were used to synthesize bio-based phenolic resins,and the activated carbon nanofibers were obtained by electrospinning and one-step carbonization activation.Fourier transform infrared and differential scanning calorimetry were used to characterize the structural and thermal properties.The results reveal that the apparent activation energy of the curing reaction is 89.21 kJ·mol–1 and the reaction order is 0.78.The activated carbon nanofibers show a uniform diameter,specific surface area up to 1100 m^(2)·g^(-1),and total pore volume of 0.62 cm^(3)·g^(-1).The electrode demonstrates a specific capacitance of 238 F·g^(-1)(0.1 A·g^(-1))and good rate capability.The symmetric supercapacitor yields a high energy density of 26.39 W·h·kg^(-1)at 100 W·kg^(-1)and an excellent capacitance retention of 98%after 10000 cycles.These results confirm that the activated carbon nanofiber from bio-based phenolic resins can be applied as electrode material for high-performance supercapacitors.

废弃风电叶片材料的机械法回收及资源化利用技术研究

随着风电行业的高速发展,风电叶片也逐渐进入到了退役或更新阶段,预计到2025年后,每年将有数万吨的废弃风电叶片需要处理。以退役风电叶片材料资源化利用的一种方式(机械回收及资源化利用技术)为例,主要从热固性复合材料破碎机械设备和产物再利用进行分析,对机械回收法处理废弃风电叶片材料提出建议,可作为废弃风电叶片材料资源化利用的参考。

浸渍胶膜纸饰面人造板常见问题及解决办法

浸渍胶膜纸压贴固化后有耐磨、耐划痕、耐高温、耐酸碱腐蚀等特性,并具有装饰性强、使用寿命长和性价比高等优点,广泛应用于人造板饰面。本文深入剖析浸渍胶膜纸饰面人造板常见的外观质量和理化性能问题及其产生的原因,并提出相应的解决方案,以期为行业提高浸渍胶膜纸饰面人造板质量提供参考。