Effect of addition of an interfacial agent on the joint strength of a nitrile-phenolic structural adhesive

A study was conducted to determine the effect of adding p-cresol formaldehyde (PCF) resin as an interfacial agent to a nitrile rubber (NBR)-phenol formaldehyde (PF) structural adhesive, on its joint strength, stress-strain properties, glass transition temperature (T_g), and morphology. The addition of PCF resin up to 20% showed a remarkable improvement in joint strength accompanied by an improvement in the mechanical properties. Scanning electron microscopy and DSC analysis (T_g) showed that the NBR/PF blend is a two-phase system and with the addition of PCF resin, the two phases tend to become continuous and the T_g of the NBR phase is increased. From the results obtained we propose that PCF acts as an interfacial agent and facilitates the bonding between the two phases, which improves the mechanical properties, and hence the joint strength. PCF contents above 20% produced a decrease in the joint strength, which is attributed to decreased toughness resulting from the high cross-linking of the NBR phase.     

Reactive bonding of natural rubber to metal by a nitrile–phenolic adhesive

The mechanism of adhesive bonding of rubber to metal using an interlayer of bonding agent (adhesive) is discussed with respect to various physical and chemical events such as adsorption at the metal surface, chemical crosslinking within the adhesive, interdiffusion, and formation of interpenetrating networks at the rubber–adhesive interface. An investigation on the peel strength of a natural rubber (NR)–adhesive–metal joint, made by vulcanization bonding using nitrile–phenolic adhesive containing various concentrations of toluene diisocyanate–nitrosophenol (TDI–NOP) adduct, is presented. A single‐coat adhesive, consisting of a p‐cresol phenol formaldehyde resin, nitrile rubber (NBR), and vulcanizing agents in methyl ethyl ketone solvent, was selected for the study. Considerable improvement in the peel strength was obtained by the incorporation of TDI–NOP adduct into the nitrile–phenolic adhesive. The peel strength increases as the concentration of TDI–NOP adduct in the adhesive composition increases, then levels off with a transition from interfacial failure to cohesive tearing of rubber. The peel strength improvement is believed to be attributed to the interfacial reactions between the bonding agent and natural rubber, when TDI–NOP adduct is incorporated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2597–2608, 2001     

Effect of a reactive interfacial agent on the properties of a nitrile-rubber-modified epoxy film adhesive

Reactive interfacial agents are often used to homogenise the morphology of immiscible polymer blends and to improve the level of adhesion between the phases to achieve enhanced properties. This paper demonstrates the ability of hydroxyl methyl bisphenol A (HMBPA) to function as a reactive interfacial agent (compartibilizer) in a nitrile-epoxy film adhesive made from nitrile rubber (NBR) and solid epoxy resin blend. The curing of the adhesive film was achieved at 170° C by adding dicyandiamide, a latent curing agent for epoxy resin, and rubber vulcanising agents. Hydroxyl methyl bisphenol A resins with different hydroxyl methyl content, synthesised by the base-catalysed reaction of bisphenol A and formaldehyde in various mole ratios, were used to compatibilize a blend of nitrile rubber (NBR) and epoxy resin 50/50wt/wt. The effect of addition of HMBPA on the morphology, adhesive, thermal, and mechanical properties of the adhesive film was investigated. The nitrile-epoxy adhesive films were characterised by measurements of adhesive joint strength, stress-strain properties, DSC, TGA, TMA, DMA, and SEM. Results revealed that significant improvement in joint strength occurred at low levels of HMBPA, and the optimum strength was obtained at about 15 wt% of HMBPA in the blend. The hydroxyl methyl content in HMBPA was found to influence the properties of the adhesive film. The concept of strengthening the interphase between NBR and epoxy through the coupling reactions of HMBPA was used for interpreting the results. The effect of addition of silica, alumina, and aluminium fillers on the properties of the nitrile-epoxy adhesive film was also studied, and a comparison of properties with and without HMBPA is presented.     

Mechanical properties and microstructure of acrylonitrile–butadiene rubber vulcanizates reinforced by in situ polymerized phenolic resin

The phenolic resin (PF) was incorporated into acrylonitrile–butadiene rubber (NBR) vulcanizates by in situ polymerization during the vulcanization process. It was found that the tensile strength, tearing strength, and tensile strength (300% elongation) could be considerably enhanced 59.4, 80.2, and 126.4%, respectively, at an optimum PF content of only 15 phr, but the elongation at break and shore A hardness were only slightly affected on the basis of silica‐reinforced NBR vulcanizates. A systematic study of the PF structure formed within the NBR matrix using various experimental schemes and procedures has revealed that the PF resin would form the localized discontinuous three‐dimensional interconnected network structures in the NBR matrix. The substantial reinforcement of PF on the mechanical properties of vulcanized NBR were attributed to the morphology, high flexibility, and moderate stiffness of the PF phases and their excellent bonding with rubbers through “rubber to rubber” and interface layer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

稻草焦油替代苯酚合成酚醛树脂胶黏剂的研究

用稻草焦油部分替代苯酚合成酚醛树脂胶黏剂,并对其性能进行了分析。实验结果表明,稻草焦油替代量对所合成的酚醛树脂胶黏度和胶合强度特性影响较大,当稻草焦油添加量为25g,即替代量达到19．2％时,制备的酚醛树脂胶黏度适中,游离甲醛质量分数低于0．5％,具备较高的胶合强度,并且胶合强度达到GB／T9846—2004对Ⅰ类胶合板的要求。由于稻草焦油的加入降低了胶黏剂的成本,其所制得的胶黏剂有良好的应用前景。     

Direct adhesion of fluorinated rubbers to nickel-plated steel and nitrile rubber during curing using the tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol

A new curing agent, the tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol (TATT) for fluorinated rubber (FR) has been developed, from the point of view of making composite materials with metals and other rubbers. TATT was inferior in curing rate compared with a conventional polyol curing system, but imparted good properties to FR vulcanizates to the same extent as the polyol curing system. TATT-containing FR compounds easily adhered to electro- and electroless nickel-plated metals during vulcanization without an adhesive. The optimum concentration of TATT was around 1 phr for the peel strength of joints and the mechanical properties of vulcanizates. At a thickness exceeding 0.3 μm, nickel platings were very effective for making FR-Ni joints. In the direct adhesion between FR and nickel platings, interfacial bonds and a reinforcing layer at the interface between vulcanizates and nickel platings during vulcanization were important for obtaining FR-Ni joints of high peel strength. The newly prepared FR-Ni joints had very good heat, oil, and water resistance, compared with conventional FR-Fe joints prepared by using phenol-type adhesives. TATT was also a very effective agent for the direct adhesion between FR and NBR (nitrile butadiene rubber) during vulcanization because it acted as a common curing agent to various rubbers such as FR and NBR. Thus, TATT is a very effective curing agent for making composites of FR with various metals and elastomers.     

氯丁橡胶与金属热硫化型胶膜的研究

采用机械共混法和胶料成膜技术制备出一种酚醛树脂(PF)-橡胶型膜状胶粘剂(胶膜)。结果表明:当n(37%甲醛)∶n(苯酚)∶n(氢氧化钠)=1.8∶1∶0.1、反应温度为70℃和反应时间为2.5 h时,合成的甲阶PF具有较高的羟甲基含量(28.3%),满足PF-橡胶型胶膜的制备要求;当m(氯丁橡胶)∶m(氯化天然橡胶)∶m(PF)∶m(炭黑)=100∶(5～10)∶(70～80)∶40、m(PF)∶m(硼酚醛树脂)=4∶1时,胶膜的剪切强度超过5.0 MPa、180°剥离强度超过4.0 kN/m且胶接件的破坏形式多为橡胶内聚破坏;该胶膜具有较好的热稳定性(热失重温度为300℃左右),满足氯化橡胶生胶片与金属之间的热硫化胶接要求;该胶膜与适宜底胶配合而成的双涂型胶接体系,可实现氯化橡胶生胶片与树脂基复合材料之间的热硫化胶接。     

Effect of acrylonitrile content of acrylonitrile butadiene rubber on mechanical and thermal properties of dynamically vulcanized poly(lactic acid) blends

We report here the morphology, thermal and tensile properties of poly(lactic acid) (PLA) blends composed of acrylonitrile butadiene rubber (NBR) with different acrylonitrile contents with/without dynamic vulcanization by dicumyl peroxide (DCP). The interfacial tension of PLA and NBR measured by contact angle measurement decreased as the acrylonitrile content of NBR decreased. Likewise, SEM images showed that the rubber particle size reduced with decreasing acrylonitrile content owing to the stronger interfacial adhesion between the PLA matrix and NBR domains. Incorporation of DCP at 1.0 phr for dynamic vulcanization led to higher crosslink density and, in turn, optimal tensile strength and tensile toughness as a result of the action of PLA‐NBR copolymer as a reactive compatibilizer. The dynamic vulcanization of the blends containing low acrylonitrile NBR gave the most improved tensile properties because the free radicals from DCP decomposition preferentially attacked the allylic hydrogen atoms or double bonds of the butadiene backbone. Accordingly, more NBR macroradicals were generated and probably more PLA‐NBR copolymers were produced. Moreover, further addition of DCP at 2.0 phr provided a large amount of crosslinked NBR gel, which significantly degraded the tensile properties. From the DSC results, dynamic vulcanization lowered the cold crystallization temperature, implying an improvement of cold crystallization. Finally, TGA results showed a higher degradation temperature as a function of DCP content, which suggested that thermal stability increased due to stronger interfacial adhesion as well as higher gel content. © 2019 Society of Chemical Industry     

EFFECT OF A REACTIVE INTERFACIAL AGENT ON THE PROPERTIES OF A NITRILE-RUBBER-MODIFIED EPOXY FILM ADHESIVE

Reactive interfacial agents are often used to homogenise the morphology of immiscible polymer blends and to improve the level of adhesion between the phases to achieve enhanced properties. This paper demonstrates the ability of hydroxyl methyl bisphenol A (HMBPA) to function as a reactive interfacial agent (compartibilizer) in a nitrile-epoxy film adhesive made from nitrile rubber (NBR) and solid epoxy resin blend. The curing of the adhesive film was achieved at 170° C by adding dicyandiamide, a latent curing agent for epoxy resin, and rubber vulcanising agents. Hydroxyl methyl bisphenol A resins with different hydroxyl methyl content, synthesised by the base-catalysed reaction of bisphenol A and formaldehyde in various mole ratios, were used to compatibilize a blend of nitrile rubber (NBR) and epoxy resin 50/50wt/wt. The effect of addition of HMBPA on the morphology, adhesive, thermal, and mechanical properties of the adhesive film was investigated. The nitrile-epoxy adhesive films were characterised by measurements of adhesive joint strength, stress-strain properties, DSC, TGA, TMA, DMA, and SEM. Results revealed that significant improvement in joint strength occurred at low levels of HMBPA, and the optimum strength was obtained at about 15 wt% of HMBPA in the blend. The hydroxyl methyl content in HMBPA was found to influence the properties of the adhesive film. The concept of strengthening the interphase between NBR and epoxy through the coupling reactions of HMBPA was used for interpreting the results. The effect of addition of silica, alumina, and aluminium fillers on the properties of the nitrile-epoxy adhesive film was also studied, and a comparison of properties with and without HMBPA is presented.     

Effect of dynamic vulcanization on properties and morphology of nylon/SAN/NBR blends: A new compatibilization method of nylon/ABS blends

Dynamically vulcanized blends of nylon, styrene–acrylonitrile copolymer (SAN), and nitrile–butadiene rubber (NBR) were examined for mechanical properties, Shore D hardness, Vicat softening temperature, impact process, and phase morphology. The effect of a curing system such as phenolic formaldehyde resins (PF), dicumylperoxide (DCP), and a sulfur system on the mechanical properties of the nylon/SAN/NBR blends was studied, and dynamic vulcanization with a PF system was found to lead to outstanding toughness of the blends. The effect of PF content on the mechanical properties, Shore D hardness, and heat resistance of the nylon/SAN/NBR blends was also investigated. With increasing PF content the notched‐impact strength and Vicat softening temperature (VST) of the nylon/SAN/NBR (50/25/25) blends evidently improved, but tensile strength and Shore D hardness of the blends changed slightly. It can be concluded that the nylon/SAN/NBR (50/25/25) blends dynamically vulcanized by high‐content PF can attain excellent comprehensive mechanical properties, especially supertoughness, at room temperature. SEM was used to investigate the effect of dynamic vulcanization on disperse‐phase particle size, particle size distribution, and phase morphology. It was obvious that disperse‐phase particle size decreased with an increasing PF content. Thermal behavior and miscibility of dynamically vulcanized nylon/SAN/NBR with PF were investigated by DMTA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2057–2062, 2003     

冷压型脲醛树脂固化剂的初步应用

聚乙酸乙烯酯乳液可以作为脲醛树脂固化剂的主要组份或改性剂，为探讨聚乙酸乙烯酯乳液及甲醛捕捉剂A对脲醛树脂性能的影响。采用改性聚乙酸乙烯酯乳液、甲醛捕捉剂A、非离子型表面活性剂以及其它添加剂等配制出一种冷压型固化剂，并测定了脲醛树脂的pH值、固化时间和冷压粘接强度，结果表明该固化剂有助于提高脲醛树脂的固化特性和粘接性能，同时也指出该固化剂与脲醛树脂配比以10％-15％为宜，甲醛捕捉剂A用量以该固化剂中聚乙酸乙烯酯乳液质量的20％-40％为宜。     

竹焦油替代苯酚合成酚醛树脂胶黏剂的研究

研究了用竹焦油部分替代苯酚合成酚醛树脂胶黏剂,并对其性能进行分析。实验结果表明,竹焦油替代量对所合成的酚醛树脂胶黏度和胶合强度特性影响较大,当竹焦油添加量为 30g,即替代量达到 12.5% 时,制备的酚醛树脂胶黏度适中,游离甲醛含量低于 0.5%,具备较高的胶合强度,并且胶合强度达到 GB/T 9846-2004对Ⅰ类胶合板的要求。由于竹焦油的加入降低了胶黏剂的成本,其所制得的胶黏剂有良好的应用前景。     

聚氨酯弹性体与金属粘接的研究

以浇注型聚酯或聚醚聚氨酯弹性体为柔性材料,铁或铝金属为刚性材料,采用5种粘合剂,进行了粘接实验。实验数据表明,聚氨酯弹性体硬度较高时,柔性材料与金属粘接的剥离强度最高可达31 kN/m,聚酯型聚氨酯弹性体与金属粘接比聚醚型聚氨酯弹性体的粘接性能好。     

Enhancement of mechanical strength associated with interfacial tension between barium titanate and acrylonitrile–butadiene rubber with different acrylonitrile contents by surface modification

Acrylonitrile–butadiene rubber (NBR) with different acrylonitrile (ACN) contents was filled with barium titanate (BT) to prepare the polymer dielectrics. The neat NBR, NBR/untreated BT, and NBR/bis‐(γ‐triethoxysilylpropyl)‐tetrasulfide (silane coupling agent KH845‐4) modified BT (MBT) composites were prepared. At low ACN content (ACN content 20 wt %), the tensile strength of the NBR/MBT composites increased by 173.6% from 2.69 to 7.36 MPa compared to the neat NBR. The pleasing results were not found in those composites with high ACN content. Both surface modifications of BT and NBR with low ACN content would result in lower interfacial tension between BT and NBR. A strong interfacial adhesion was observed between MBT and NBR with 20 wt % ACN content. The interfacial adhesion had great contribution to the mechanical strength of composites. Moreover, the dielectric properties of composites were also investigated in detail. The addition of BT enhanced the dielectric constant of composites markedly. This study can be applied in manufacturing electronic devices, which are subjected to oily environments for a long time. At the same time, the study can provide some help for researchers to select the polymer matrix and the appropriate surface modification agent of functional filler. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45936.     

AS/NBR/HSB三元共混体系的动态硫化

采用动态硫化方法制备了丙烯腈-丁二烯共聚物/丁腈橡胶/高苯乙烯树脂（AS/NBR/HSB）三元共混热塑性弹性体，研究了NBR中丙烯腈质量分数，橡塑比和硫化剂对共混体系性能的影响。结果表明，动态硫化显著提高了共混材料的拉伸强度和扯断伸长率，酚醛树脂是AS/NBR，HSB共混体系比较理想的动态硫化交联剂；采用HSB，NBR，AS三元共混，共混材料的拉伸强度和扯断伸长率得到良好的平衡；差示扫描量热分析表明，该三元共混材料具有NBR和AS两相的玻璃化转变温度，说明该体系是典型的不相容体系。     

Effect of curing agent on interfacial adhesion in acrylic polymer-based laminates

The effect of crosslinking on interfacial adhesion between an acrylic elastomer and poly(methyl methacrylate) has been studied using a 90° peel test. Elastomers were master-batched with a 1 : 10 sulfur/sodium mixture. The compounded elastomer was then bonded with poly(methyl methacrylate) by in situ curing at various temperatures. Variations in the curing affect both the mechanism of adhesion and separation. The relationship between peel strength and crosslink density is found to be P = kM_c. Crosslinking at relatively low temperatures produced a partially crosslinked elastomer that leads to high peel strengths. When crosslinked at 180°C, the acrylic elastomer was completely cured, and the peel strength decreased by more than 80%. This is consistent with an optimum level of crosslinking required for peel strength. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1277–1284, 1998     

硅烷偶联剂对电场下丁腈橡胶与铁硫化粘接性能的影响

采用电化学反应的作用方法,研究硅烷偶联剂对丁腈橡胶（NBR）与铁（Fe）的热硫化粘接性能的影响。通过对胶接破坏表面进行扫描电镜以及能谱观察分析,明晰了NBR-Fe粘接界面层的结构特征,并对影响粘合性能以及硫化胶物理机械性能的因素进行了研究分析。结果表明,施加的电场强度、导电填料种类以及硅烷偶联剂的用量对粘合性能作用明显;硅烷偶联剂用量变化不仅对粘合性能影响较大,而且影响NBR硫化胶的导电性及物理机械性能。     

抗硫化返原剂对钢丝粘合胶性能的影响

研究添加抗硫化返原剂和采用抗硫化返原剂并用替代间-甲粘合体系对钢丝粘合胶性能的影响.结果表明,添加抗硫化返原剂PK900和HTS以及Z500,胶料硫化返原率明显降低,过硫化胶的物理性能保持率提高,其中PK900适用于变形较小的带束层胶料,Z500适用于变形较大的胎体帘布胶;采用抗硫化返原剂PK900和HTS并用替代间-甲粘合体系,胶料粘合性能保持不变,生热降低,硫化返原率较高,适用于变形较大的胎体帘布胶.     

发泡剂对三聚氰胺甲醛泡沫塑料性能的影响

用多聚甲醛代替部分甲醛溶液,与三聚氰胺在pH值为8.5～9.5、温度在85℃条件下发生羟甲基化反应,制备固含量≥65%的树脂,加入固化剂和乳化剂,用发泡剂进行发泡,讨论了不同种类的发泡剂对三聚氰胺甲醛树脂发泡理化性能的影响。结果表明,三聚氰胺甲醛树脂"泡孔"是开孔结构,MD I发泡剂能提高树脂的强度,NaH-CO3发泡剂可以提高树脂的阻燃性能,AIBN发泡剂能制备出高发泡材料。     

黏合增进剂PM-18在输送带胶料中的应用

主要研究了黏合增进剂PM-18在输送带胶料中的应用。试验结果表明,在尼龙、聚酯带贴胶配方中加入15份PM-18,可提高布与布、胶与布间的黏合强度,满足此类输送带的使用要求;在钢丝绳芯输送带黏合胶配方中加入15份PM-18,可获得胶料与镀锌钢丝绳良好的初始黏合力和老化后的黏合力,远高于GB/T9770标准,能够满足钢丝带长期使用的要求。通过加入黏合增进剂PM-18,在满足输送带使用要求的同时,又可使配方成本得到大幅度降低。