Adhesive and Mechanical Properties of Reactive Polysulfone Modified Epoxy Resins

The diglycidyl ether of bisphenol-A epoxy resin (EPON 828®) was cured with 4,4′-diaminodiphenylsulfone (DDS) and, optionally, an animophenyl functional reactive polyethersulfone (R-PES, ? M_n ?=10k) as a co-curing agent. Commercial polysulfone, Udel® P-1700, was also utilized to afford epoxy-Udel® blends (or semi-IPNs). Cured epoxy polymers were subjected to T_g determinations, plane strain fracture toughness (K_IC) tests, adhesive bond strength measurements, tensile tests and chemical resistance studies. The morphologies of the fractured samples were studied by SEM and correlated to the property changes. Only the reactive polysulfone modification improved both fracture toughness and adhesive properties without detracting from the good mechanical properties and chemical resistance.     

Mechanical Properties of Bismaleimides Modified Polysulfone Epoxy Matrices

Epoxy resin has been chemically modified using 4, 8, and 12% of bisphenol-A based polysulphone along with three types of bismaleimides, namely [N, N′-bismaleimido-4,4′-diphenylmethane (BMI-1), 1,3-bis (maleimido) benzene (BMI-2) and 1,1′-bis (4-maleimidophenyl) cyclohexane (BMI-3)]. The epoxy hybrid matrices developed, in the form of castings, were used to characterize their mechanical properties like tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, hardness, and dynamic mechanical analysis as per ASTM standards. Data obtained from mechanical studies indicate that the introduction of hydroxyl terminated polysulfone into epoxy resin enhanced the value of impact strength to the extent of 48% due to the formation of flexible graft structures. Similarly, the incorporation of bismaleimides into epoxy resin also improved both tensile and flexural behavior of epoxy resin. Further, the introduction of combination of both polysulfone and bismaleimides into epoxy resin improved the mechanical properties according to their percentage content. Among the bismaleimides-modified polysulfone epoxy matrices, the epoxy matrix modified with 8% polysulfone and 8% BMI-2 exhibited better mechanical properties than other modified epoxy matrices.     

Fracture Behaviour of Thermoplastic Modified Epoxy Resins

This work has shown that the addition of polyetherimide (PEI) can significantly increase the toughness of highly cross-linked epoxy resins, whilst retaining a high T_g and modulus. These combined properties indicate the potential of PEI modified epoxy resins for use as matrices for advanced composite materials. In terms of G_IC, addition of 20wt% PEI raised the toughness by a factor of eight. Evidence from SEM fracture surfaces suggests that the toughening mechanism operating in bulk PEI modified epoxy resin is ductile drawing of the PEI. Carbon fibre composites based on 30wt% PEI modified epoxy resin matrices show considerable improvement in toughness at low and high strain rates when compared with CFRP possessing unmodified or 20wt% modified PEI content epoxy resins.     

有机硅改性环氧树脂的合成与性能

热熔法制备了系列聚甲基苯基硅氧烷(PMPS)改性环氧树脂,通过环氧值、红外光谱(IR)和凝胶色谱(GPC)分析表明,有机硅接枝到了环氧树脂上,且环氧基保持不变。探讨了改性方法、有机硅含量对改性树脂固化体系的微观形态、韧性及耐热性的影响。实验表明,当m(E-20)∶m(DC-3074)=7∶3时,化学改性树脂固化体系的韧性和耐热性能明显提高,玻璃化转变温度(Tg)为88.33℃,质量损失50%时的热分解温度(Td)为487.80℃,分别比物理改性环氧树脂提高了52.63℃和36.75℃,同时此改性树脂固化物还具有优良的涂膜性能。     

有机硅改性环氧树脂的制备及其性能研究

利用三种乙氧基硅烷单体混合不完全水解合成含乙氧基的有机硅低聚物,使其与环氧树脂反应成功制备出有机硅改性环氧树脂。探讨了不同水解用水量的有机硅对改性树脂固化物冲击强度、弯曲强度和热稳定性的影响。结果表明,当水解用水量为完全水解用水量的0.5倍时,环氧树脂固化物的耐热性和韧性均有明显提高,冲击强度达14.07 kJ/m2,弯曲强度达26.73 MPa,50 %的质量热损失温度达424 ℃;比未改性的纯环氧树脂分别提高了10.23 kJ/m2,6.98 MPa和23 ℃。     

有机硅改性环氧树脂的制备及其性能研究

以3种有机氯硅烷单体水解制备有机硅单体,有机硅单体改性了环氧树脂,水解条件为温度35～40℃,时间1～1.5 h,用水量n(H2O)∶n(Cl)=(6～7)∶1。通过红外光谱分析表明,有机硅主要是与环氧树脂中羟基发生化学反应。对环氧树脂改性前后的力学性能、耐热性和防潮性进行测试,结果表明,当n(R)/n(Si)为1.5时,拉伸强度可达23.91 MPa,弯曲强度达到29.24 MPa,冲击强度达到10.02 kJ/m2,50%的质量热损失温度431℃,分别比改性前提高了3.86 MPa,9.49 MPa,6.18 kJ/m2,30℃;同时,改性后树脂防潮性能也得到了提高。     

有机硅改性环氧树脂的制备及性能

以自制的乙酰丙酮钛为催化剂,有机硅树脂TSR144为改性剂,通过化学改性的方法制备了一系列有机硅改性环氧树脂.探讨了有机硅加入量对改性环氧树脂固化物结构及性能的影响,采用IR、TGA/DTG技术对改性环氧树脂进行了表征及分析,并利用扫描电镜( SEM)观察断面的微观形貌.结果表明:随着有机硅含量增加,样品最大分解速率时的温度(T1max)呈S型曲线变化趋势;当有机硅的含量为16.7％时,复合体系的力学性能显著改善,其拉伸强度、断裂伸长率分别达到54.86 MPa,9.43％,比未改性的纯环氧树脂分别提高了8.54 MPa,2.71％.     

端氨基聚醚-环氧树脂粘结剂的制备与力学性能

本文采用离去基团法,合成了双端氯代的聚乙二醇和端氨基聚醚(ATPE)。通过红外光谱分析研究了反应时间对双端氯代的聚乙二醇和端氨基聚醚结构的影响,以及ATPE用量对端氨基聚醚-环氧树脂粘接剂力学性能的影响规律。结果表明,ATPE中同时含有柔性聚醚链段和刚性基团,实现了对环氧树脂的增强增韧。当ATPE与E-44质量比为0.67时,胶粘剂的综合力学性能最好,附着力高达24.70 MPa,剥离强度103.9 N·cm-1,柔韧性优于2 mm,耐冲击强度超过50 kg·cm。     

苯并恶嗪改性环氧树脂灌封胶黏剂性能的研究

苯并恶嗪作为一种可以中温固化的,无挥发份产生的耐高温树脂,目前在灌封胶黏剂领域还没有被应用.通过苯并恶嗪改性环氧树脂可以提高其耐热能,并保持原有力学性能.制备了一种苯并恶嗪改性环氧树脂灌封胶黏剂.采用红外光谱研究了其固化前后的结构变化,采用差热分析法对其固化行为进行了分析,通过热重法和动态黏弹法研究了其耐热性能.胶黏剂力学性能研究结果表明该体系在130 ℃固化5 h,具有良好的耐热性和力学性能.     

改性环氧丙烯酸酯胶粘剂的合成与性能

本文研究了环氧丙烯酸酯的改性，采用双马来酰亚胺、环氧树脂、丙烯酸酯、改性剂为主要原料合成了改性环氧丙烯酸酯胶粘剂．运用IR、DSC等分析测试手段研究了该胶粘剂的固化行为。运用TGA、DTA等分析手段研究了该胶粘剂固化后的热稳定性．同时，用改性环氧丙烯酸酯胶粘剂制得了聚酰亚胺薄膜挠性印刷电路基板并测试了有关性能．     

Toughening of Epoxy Resins with Thermoplastics: 3. An Investigation into the Effects of Composition on the Properties of Epoxy Resin Blends

Three different epoxy resins, based on the diglycidylether of bisphenol A (DGEBA), triglycidyl-p-aminophenol (TGPAP) and tetra-glycidyldiaminodiphenylmethane (TGDDM), which are di-, tri- and tetrafunctional, respectively, were mixed in varying proportions and cured with both 3,3′-diaminodiphenylsulphone and 4,4′-[1,4-phenylene(1-methylethylidene)]bis(2,6-dimethylbenzenamine) (EPON 1062-M from Shell). All the blends could be satisfactorily cured and gave homogeneous materials. The dynamic mechanical and fracture properties of the cured materials were measured. It was found that the glass transition temperature varied with composition systematically, whereas values of the strain energy release rate (G_1c) and the stress intensity factor (K_1c) showed relatively small variations with the blend composition. Toughened epoxy resins were prepared by adding a polyetherimide (PEI), in varying proportions, to the resin mixture. The ‘toughenabilities’ of different resins, or resin mixtures, were compared. This showed that the 75/25 TGPAP/DGEBA resin mixture was the most toughenable. Adding 20% of PEI led to a more than three-fold increase of the G_1c value. © of SCI.     

高沸醇木质素环氧树脂的合成与性能研究

利用高沸醇木质素的化学活性,直接与环氧氯丙烷反应,生成木质素环氧树脂和木质素改性双酚A型环氧树脂,用环氧值、红外光谱、TGA和DSC等对树脂进行表征,并与未改性的双酚A型环氧树脂进行对比。结果表明,高沸醇木质素很容易合成木质素环氧树脂,其最佳合成条件是:n(ECH)∶n(-OH)=8,温度55～60℃,碱浓度为5%;高沸醇木质素环氧树脂能显著提高环氧树脂的耐溶剂性和耐热性。     

有机硅磷杂化改进环氧树脂耐热性、韧性和阻燃性的研究

将聚甲基三乙氧基硅烷（PTS）与一种合成的含磷硅烷偶联剂以一定配比进行反应,所得改性剂添加到双酚A环氧树脂E51/酚醛树脂固化体系中,对改性环氧树脂固化产物的玻璃化转变温度、热失重、冲击强度、拉伸强度、极限氧指数进行了测试,并对固化产物的表面形貌进行了SEM观察。结果表明,在保持拉伸强度基本不变的同时,改性环氧树脂固化物的玻璃化转变温度、高温热稳定性、冲击强度、极限氧指数均有不同程度提高,使改性环氧树脂的性能得到综合提升。     

环氧化硅油改性邻甲酚醛环氧树脂的研究

采用侧基环氧化硅油(ES)及其改性物(PSA)改性邻甲酚醛环氧树脂(ECN),制备出一系列可用于电子封装等具有高韧性高耐热性的环氧基料。通过对固化物的冲击强度、拉伸强度、断裂伸长率和玻璃化转变温度(Tg)以及断裂面形态的测定,探讨了改性方法、有机硅组成与含量等对改性材料性能的影响。结果表明,用有机硅改性ECN后,其韧性和耐热性均有不同程度的提高,且环氧值高的ES和PSA的改性效果较好。其中环氧树脂经10份(质量份数,下同)ES-16或10份PSA-16改性后,韧性和耐热性均提高,符合电子封装等材料的改性要求,后者的耐热效果更为显著,Tg达183.46℃,比未改性环氧树脂提高了近20℃。     

环氧树脂增韧剂CYH-277的应用性能

环氧树脂固化物存在质脆、冲击性能差等缺点,限制了它的应用,以活性增韧剂CYH-277对环氧树脂进行增韧,利用红外光谱分析对活性增韧剂的结构进行了表征,考察了CYH-277对环氧树脂粘度的影响,初步研究了活性增韧剂CYH-277在环氧树脂涂料中的应用。结果表明：CYH-277能够有效降低环氧树脂的粘度,调整施工性能;可以有效改善环氧树脂的冲击性能,增韧效果也明显。     

反应性端基聚丁二烯系列液体橡胶在环氧树脂改性增韧方面的应用

综述了含反应性端基聚丁二烯系列液体橡胶（以下简单PBLR）品种、性能及特点，概括比较了PBLR改性增韧环氧树脂方法及特点；分别列举了PBLR改性环氧树脂在微机电浇注料，树脂砂轮，水利机械涂敷，电子灌封及飞机粘合剂等方面的应用。     

有机硅改性提高环氧树脂韧性和耐热性的研究

用聚甲基三乙氧基硅烷(PTS)通过物理和化学改性两种方法,成功制备了一系列有机硅改性环氧树脂。通过对化学改性产物的红外光谱、环氧值和相对分子质量及分布的测定,表明有机硅已成功引入环氧树脂。对两种改性方法所得固化物的玻璃化转变温度(Tg)、拉伸强度及断裂伸长率、热稳定性、微观结构进行了分析测定,探讨了改性方法、有机硅含量等对材料性能的影响。结果表明,化学改性环氧树脂产物具有更为优良的性能,双酚A型环氧树脂E-44(简写EP)通过PTS化学反应改性,当m(EP)∶m(PTS)=100∶10时,其固化物拉伸强度达58.36 MPa,断裂伸长率达11.65%,Tg达169.82℃,50%的质量热损失温度达到487℃;比未改性的纯环氧树脂分别提高了9.42 MPa,4.91%,17.29℃,39℃。     

氨基封端的聚砜增韧改性环氧树脂复合材料的制备及性能研究

合成一种氨基封端的聚砜(PSF-NH₂)并添加至环氧树脂中制备复合材料。采用傅里叶变换红外光谱(FTIR)、热重分析(TG)、动态力学分析(DMA)和扫描电子显微镜(SEM)等方法对复合材料的结构与性能进行了研究。研究表明,添加适量的PSF-NH₂可以使复合材料保持均相体系,当PSF-NH₂含量为2.50%时,冲击强度相比于纯树脂提高了95.02%。环氧树脂的韧性得到提高的同时拉伸和弯曲性能也有所改善,且复合材料耐热性基本保持不变。     

Synthesis and Properties of Interpenetrating Polymer Networks Composed of Epoxy Resins and Polysulphones with Cross-linkable Pendant Vinylbenzyl Groups

Polysulphones with cross-linkable pendant vinylbenzyl groups (PSF-VB) were prepared via chloromethylation of commercial polysulphones. The curing reactivity of PSF-VB was investigated by differential scanning calori-metry. Interpenetrating polymer networks (IPNs) were prepared based on bisphenol A diglycidyl ether (DGEBA) and PSF-VB, where DGEBA was cured by 4,4′-diaminodiphenyl sulphone and VB groups of PSF-VB were radically polymerized using dicumyl peroxide (DCP). Polysulphones having pendant benzyl groups (PSF-Bz) were also prepared and used as non-reactive modifiers. The fracture toughness (K_IC) for the resulting epoxy/PSF-VB IPN increased by 65% with no loss of mechanical properties on 10wt% addition of PSF-VB (7·9mol% VB unit, MW 74000). Non-reactive PSF-Bz was less effective than PSF-VB. Although the PSF-Bz modified resin had a particulate structure, the morphologies of the PSF-VB/epoxy IPNs were not clear from scanning electron micrographs. Furthermore, the epoxy/PSF-VB IPNs had higher solvent resistance than the epoxy/PSF-Bz blends. Morphological behaviour, modification results and high solvent resistance of the cured epoxy/PSF-VB resins indicate that cross-linked PSF-VB and the epoxy network entangled fully in the presence of DCP. © of SCI.     

亚胺改性环氧树脂胶黏剂的研究

采用端羧基亚胺中间体对环氧树脂进行改性,用芳香胺做固化剂,制备了亚胺改性环氧树脂胶黏剂.研究了端羧基亚胺中间体的种类及用量、固化剂种类及用量、固化条件等因素对胶黏剂性能的影响.结果表明,采用分子中含有砜基的亚胺中间体对环氧进行改性、用DDS做固化剂制得的胶黏剂的性能最好.亚胺中间体用量为60phr～70phr、固化剂用量控制在固化剂活泼-H/环氧基为0.6～0.7时,胶黏剂的综合性能较好.适合该胶黏剂的固化条件为200℃/2h 220℃/4h.