Structure and adhesion properties of linear low‐density polyethylene powders grafted with acrylic acid via ultraviolet light

The structure and adhesion properties of linear low‐density polyethylene (LLDPE) powder grafted with acrylic acid (AA) via ultraviolet light (UV) were studied by Fourier transform infrared spectroscopy (FTIR), electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), and water contact angle, peel strength, and graft degree measurements. The results show that the chemically inert LLDPE powder can be graft‐copolymerized with AA via this photografting method. The graft degree increases with the ultraviolet irradiation time. The hydrophilicity of the grafted LLDPE powder and the peel strength of high‐density polyethylene (HDPE)/steel joint with the grafted LLDPE powder used as hot‐melt adhesive are improved considerably, as compared to that with the ungrafted LLDPE powder. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2549–2553, 2006     

太阳能电池封装用EVA胶膜性能的研究

采用特殊结构的硅烷偶联剂对乙烯-乙酸乙烯酯共聚物(EVA)进行化学熔融接枝。利用硅烷接枝的EVA作为基础树脂,辅以复合引发剂、助交联剂以及各种老化助剂,经过热挤出成型制备出EVA胶膜母料。考察了复合引发剂用量对EVA胶膜交联度的影响,研究了硅烷接枝EVA和未接枝EVA胶膜的剥离强度及耐老化性能。结果表明:硅烷接枝EVA胶膜最佳的固化温度为160℃,最佳固化时间为11 min;硅烷接枝EVA具有良好的剥离强度、耐湿热和紫外光老化性能。     

Effects of surface modification by oxygen plasma on peel adhesion of pressure‐sensitive adhesive tapes

Surfaces of poly(isobutylene) (PIB) and poly(butylacrylate) (PBA) pressure‐sensitive adhesive tapes were treated by oxygen plasma, and effects of surface modification on their adhesive behavior were investigated from the viewpoint of peel adhesion. The peel adhesion between PIB and PBA pressure‐sensitive adhesive tapes and stainless steel has been improved by the oxygen plasma treatment. The surface‐modification layer was formed on PIB and PBA pressure‐sensitive adhesive surfaces by the oxygen plasma treatment. The oxygen plasma treatment led to the formation of functional groups such as various carbonyl groups. The treated layer was restricted to the topmost layer (50–300 nm) from the surface. The GPC curves of the oxygen plasma‐treated PBA adhesive were less changed. Although a degradation product of 1–3% was formed in the process of the oxygen plasma treatment of the PIB adhesive. There are differences in the oxygen plasma treatment between the PIB and PBA adhesives. A close relationship was recognized between the amount of carbonyl groups and peel adhesion. Therefore, the carbonyl groups formed on the PIB and PBA adhesive surfaces may be a main factor to improve the peel adhesion between the PIB and PBA adhesive and stainless steel. The peel adhesion could be controlled by changing the carbonyl concentration on the PIB and PBA adhesive surfaces. We speculate that the carbonyl groups on the PIB and PBA adhesive surface might provide an interaction with a stainless steel surface. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1392–1401, 2000     

聚丙烯薄膜与铜箔的粘接

通过聚丙烯薄膜和铜箔的表面处理和胶粘剂的选择,对它们的粘接进行了研究,经胶接接头的剥离强度和耐溶剂性能测试,筛选出粘接强度高、耐溶剂性能良好粘接接头,结果铜箔和聚丙烯薄膜的最高的剥离强度可达到14N/cm,与不经任何处理的空白试样相比,增加近7倍。     

Silane Modification of Carbon Nanotubes and Preparation of Silane Cross‐Linked LLDPE/MWCNT Nanocomposites

The objective of this study is to investigate the effects of carbon nanotube (CNT) content, surface modification, and silane cross‐linking on mechanical and electrical properties of linear low‐density polyethylene/multiwall CNT nanocomposites. CNTs were functionalized by vinyltriethoxysilane to incorporate the ─O─C2H5 functional groups and were melt‐blended with polyethylene. Silane‐grafted polyethylene was then moisture cross‐linked. Silanization of CNT was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and EDX analysis. Hot‐set test results showed that silane cross‐linking of polyethylene and incorporation of modified CNTs into polyethylene led to an increase in cross‐linking density and the number of entanglements resulting in a decrease in elongation. It was found that the addition of pristine multiwall carbon nanotubes (MWCNTs) and functionalized MWCNTs does not affect silane cross‐linking density. Silane modification resulted in a stronger adhesion of the silane cross‐linked LLDPE to silanized MWCNTs according to scanning electron microscopy micrographs. Additionally, the electrical tests revealed that the silane modification of CNTs results in an improvement in electrical properties of nanocomposites, while silane cross‐linking will not have an effect on electrical properties. Rheological properties of MWCNT/LLDPE nanocomposites have been studied thoroughly and have been discussed in this study. Moreover, according to TGA test results, modification of the MWCNTs led to a better dispersion of them in the LLDPE matrix and consequently resulted in an improvement in thermal properties of the nanocomposites. Crystallinity and melting properties of the nanocomposites have been evaluated in detail using DSC analysis. J. VINYL ADDIT. TECHNOL., 26:113–126, 2020. © 2019 Society of Plastics Engineers     

An investigation on wear mechanism of POM/LLDPE blends

The friction and wear properties of polyoxymethylene/linear low‐density polyethylene/ethylene‐acrylic acid (POM/LLDPE/EAA) blends are investigated on a MM‐200 wear tester. The results show that the addition of LLDPE and EAA obviously improves the friction and wear properties of POM. The friction coefficient and wear scar width of POM/LLDPE/EAA blends are much lower than those of pure POM. SEM analysis reveals that POM appears to wear by thermal softening and melting of worn surface when sliding against the stainless steel, while no severe damage but wear debris can be observed on the worn face of POM/LLDPE/EAA blend. Long‐time sliding causes the removal of molten POM from the worn surface, while the formation of the lubricated layer occurs on the worn surface for POM/LLDPE/EAA blend. DSC analysis shows that the melting temperature and the crystallinity of the worn surface for POM are improved after a long‐time sliding. Molecular orientation on the worn surface of POM is affirmed by WAXD. For POM/LLDPE/EAA blend, the improvement of the friction and wear properties is mainly owed to wear debris and lubricant layer existing between the contact surfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 48–53, 2006     

304不锈钢箔的表面处理和粘接工艺研究

研究不同表面处理和胶粘剂实现5μm胶层对0.05 mm厚304不锈钢箔的粘接。试验表明:不锈钢表面粗糙度、偶联处理、胶粘剂和工艺对粘接效果有影响。最佳工艺:不锈钢箔先用丙酮清洗,于刻蚀剂中室温震荡5 min,水和乙醇清洗,再浸泡于浓度为0.5%KH-550乙醇水溶液30 s,乙醇清洗,晾干上胶,保温压粘,不锈钢箔剥离强度可达到9.4 N/cm,并耐丙酮等溶剂浸蚀。     

Surface modification of plasma‐pretreated high density polyethylene films by graft copolymerization for adhesion improvement with evaporated copper

Surface modification of Ar plasma‐pretreated high density polyethylene (HDPE) film via UV‐induced graft copolymerization with glycidyl methacrylate (GMA) and 2‐hydroxyethylacrylate (HEA) was carried out to improve the adhesion with evaporated copper. The surface compositions of the modified HDPE surfaces were characterized by X‐ray photoelectron spectroscopy (XPS). The adhesion strengths of evaporated copper with the graft‐copolymerized HDPE films were affected by the Ar plasma pretreatment time, the monomer concentration used for graft copolymerization, and the graft concentration. Post‐treatments, such as plasma post‐treatments after graft copolymerization and thermal treatment (curing) after metalization, further enhanced the adhesion strength of the Cu/HDPE laminates. The T‐type peel strengths of the laminates involving the graft‐modified and plasma posttreated HDPE films were greater than 15 N/cm. The enhanced adhesion strength resulted from the strong affinity of the graft chains for Cu and the fact that the graft chains were covalently tethered on the HDPE surface. XPS characterization of the delaminated surfaces of the Cu/HDPE laminates revealed that the failure mode of the laminates with T‐peel adhesion strengths greater than 5 N/cm was cohesive in nature.     

Low‐temperature thermal graft copolymerization of 1‐vinyl imidazole on fluorinated polyimide films with simultaneous lamination of copper foils

A simple technique of thermal graft copolymerization of 1‐vinyl imidazole (VIDZ) on pristine and argon plasma pretreated fluorinated polyimide (FPI) films with simultaneous lamination of copper foils was demonstrated. The simultaneous thermal grafting and lamination process was carried out in the temperature range of 80–140°C under atmospheric conditions and in the complete absence of a polymerization initiator. Three different FPI samples of different chemical structures were employed in the present study. An optimum T‐peel strength about 15 N/cm was achieved for the copper/FPI laminate. The adhesion strength, however, decreased with increasing fluorine content in the FPI film. The onset of cohesive failure occurred in the FPI film for assemblies with T‐peel strength greater than 6 N/cm. The T‐peel strengths are reported as a function of the argon plasma pretreatment time of the FPI films and thermal lamination temperature. The adhesion strengths were compared to that of the similarly prepared copper/polyimide (Kapton HN) laminate. Time‐dependent water contact angle (Θ) measurements indicated that the surfaces of FPI films are significantly more hydrophobic and more resistant to water diffusion or hydration than the Kapton HN films. The surface compositions of the pristine FPI films, as well as the delaminated FPI films and copper foils were studied by X‐ray photoelectron spectroscopy. The thickness of the graft VIDZ polymer layer was in the order of 200 nm, as derived from the cross‐sectional view of the scanning electron micrograph. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1478–1489, 1999     

The effect of plasma‐polymerised silicon hydride‐rich polyhydrogenmethylsiloxane on the adhesion of silicone elastomers

BACKGROUND: Silicone elastomers have outstanding material properties including good thermal stability, low electrical conductivity, biocompatibility and resilient physical and chemical properties. These elastomers, however, exhibit relatively poor adhesion to stainless steel, and the use of a nanometre thick plasma‐polymerised primer layer as a means of enhancing this adhesion was investigated in this study. The primer coatings studied consisted of polyhydrogenmethylsiloxane (PHMS), tetraethyl orthosilicate (TEOS) and mixtures of these two liquid precursors. RESULTS: The plasma‐polymerised primer coatings were deposited onto stainless steel substrates using a PlasmaStream^? atmospheric pressure plasma jet system. Deposited coatings were examined using ellipsometry, contact angle measurements, optical profilometry, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy and scanning electron microscopy. The adhesion of silicone elastomers bonded to the primed and bare stainless steel surfaces was assessed using 45° adhesion strength measurements. Elastomer adhesion was correlated with surface energy, thickness and roughness. CONCLUSION: An up to 15‐fold increase in adhesive fracture energy was observed for silicone elastomers bonded to the primed versus untreated stainless steel. The highest adhesion was observed for a coating deposited from a PHMS‐to‐TEOS precursor molar ratio of 3 to 1. Copyright © 2009 Society of Chemical Industry     

Fusion bonding of maleated polyethylene blends to polyamide 6

Blends of linear low-density polyethylene (LLDPE) and linear low-density polyethylene–grafted maleic anhydride (LLDPE-gMA) were used to promote the adhesion to polyamide 6 (PA) in a three-layer coextruded film without using an additional adhesive or tie layer. The effect of bonding time and molecular weight (MW) of different maleated polyethylenes on the peel strength of the joints was analyzed. Direct evidence of a copolymer formed in-situ at the interfaces is also considered. The peel strength of fusion bonded layers of LLDPE/LLDPE-gMA blends with PA strongly depends on bonding time and molecular weight of the maleated polymer. Tensile properties of three-layer films, made up of PA as the central layer and LLDPE/LLDPE-gMA blends as the two external layers, are improved with increases in the maleic anhydride (MA) content in the blend. The in-situ formation of a copolymer between the MA in the blend and the terminal amine groups of the PA was confirmed by the Molau test, infrared (IR) spectroscopy, and thermal analysis (DSC).     

Improvement in the adhesion of polyimide/epoxy joints using various curing agents

An improvement in the adhesion strength of polyimide/epoxy joints was obtained by (1) introducing a functional group on the polyimide surface, (2) improving the mechanical properties of the epoxy adhesive, (3) increasing the curing temperature, and (4) using polyamic acid as an adhesion‐promoting layer. The functional group on polyimide was introduced via treatment with aqueous KOH. An adhesion‐promoting layer was formed by spin coating polyamic acid onto a modified polyimide surface. The maximum adhesion strength of the polyimide/epoxy joint was obtained using polyamic acid as both the adhesion‐promoting layer and as the curing agent. The surface energy of the modified polyimide was examined using contact angle measurements and Fourier transform infrared spectroscopy, and the peel strength was determined by the T‐peel method. The peeled surfaces were analyzed using scanning electron microscopy and X‐ray photoelectron spectroscopy.© 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 812–820, 2002     

The effect of particle size and composition on the performance of styrene/butyl acrylate miniemulsion-based PSAs

Styrene/butyl acrylate batch miniemulsion copolymerizations were performed in a 1.2 L stainless steel reactor. Conversions were monitored off-line using gravimetry and in-line using ATR-FTIR spectroscopy. The final latexes were coated on a polyethylene terephthalate carrier and dried at room temperature for 2 days. Their performance as pressure-sensitive adhesives (PSAs) was evaluated by measuring their tackiness, peel strength and shear strength. By using a constrained mixture design, the influence of particle size and copolymer composition was investigated. Particle size was found to be the most influential factor for both tack and peel strength models. Tack showed a concave upward trend whereas peel strength decreased with increasing particle size. Shear strength decreased with increasing particle size but was also significantly influenced by copolymer composition. The final forms of the models allowed 3D response surfaces to be built and an optimal adhesive performance region (highest combined tack, peel strength and shear strength) was located near the smallest particle diameter investigated with the highest styrene composition. The positive effect of smaller particles on every adhesive property relates to the tighter packing provided by smaller particles during the drying process, thus increasing the area of contact between the adhesive and the substrate.     

液体橡胶改性环氧树脂固化及应用研究

用聚丁二烯液体橡胶与环氧树脂制得聚丁二烯液体橡胶/环氧树脂(ETPB)胶粘剂。本文研究ETPB固化剂加入量对粘接和剥离强度的影响。由于该胶粘剂的粘接和剥离性能优异,所以可用于水轮机的耐磨涂层。本文对该胶粘剂在水轮机上的应用性能进行了讨论。结果表明,在ETPB中加入固化剂量为20%时,材料的粘接和剥离性能最好,并且与水轮机用不锈钢性能相比相差不大,可以作为廉价的水轮机叶片保护涂层。     

环氧化天然橡胶粘合剂的研制

本文叙述环氧化天然橡胶的合成、分析和粘合剂特性.试验表明,这粘合剂对硫化橡胶、皮革、人造革、PVC、木板、钢铁、酚醛塑料等具有高的粘合力,剥离强度达100N/2·5cm;而且具有耐水、耐酸、耐碱和耐热的特性.     

Effect of silane treatment parameters on the silane layer formation and bonding to thermoplastic urethane

Enhancing adhesion is of primary importance in preparation of insert injection molded plastic–metal hybrids. Here, the combination of coupling agent application parameters and steel oxide microstructure effects on the adhesion in thermoplastic urethane–stainless steel hybrids was studied. The stainless steel oxide structure was first modified by electrolytical polishing and subsequent oxidation treatment, then the steel was coated with N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (γ-AEAPS) prior to overmolding with thermoplastic urethane. The properties of formed silane coatings and ultimately the thermoplastic urethane–stainless steel hybrids were determined by several microscopical methods, infrared spectroscopy and mechanical testing. The bond strength of hybrids depended on the silane layer thickness. Also the stainless steel surface oxide structure had a remarkable influence on the coating formation and the resulting hybrid bond strength.     

Strength degradation in γ-aminopropyl triethoxy silane primed α-Al2O3/nylon 6 peel joints in a wet environment

Unprimed sapphire/nylon 6 peel joints (2.13 ± 0.27 Kg/cm) are found to be stronger than sapphire/polyethylene joints (0.06 ± 0.02 Kg/cm). Priming the sapphire with γ-aminopropyl triethoxy silane (γ-APS) improves the strength significantly resulting in adherend failure in the nylon. The rate and extent of degradation is lower with priming. The optimal silane thickness is about 1900 Å, obtained with a 0.3 percent γ-APS solution, for a five day exposure to water at 25°C. Peel joints made with 0.3 percent γ-APS film, both dried at 25°C (standard conditions) and dehydrated at 110°C under vacuum, fail cohesively when exposed at 25°C. Increasing the exposure to 55°C in a second step results in strength degradation only with dehydrated films. Lower joint strengths are obtained with five days exposure as compared to one day exposure. However, if the temperature is raised to 65°C the joints primed with standard dried films now begin to degrade and lose 90 percent of their strength in five days. Further, the nylon 6 peel joints made with a 0.3 percent γ-APS film, dehydrated for three days prior to lamination, show 10 times greater wet strengths than the corresponding PE joints. Failure surface analyses by ESCA and SEM suggest that failure locus due to water degradation is within the γ-APS layer and the failure mode is cohesive. Failure mechanics during testing the wet peel joints may also cause a partial interfacial failure mode. The effects of the silane film thickness, dehydration condition, time, and temperature dependence of the peel strength degradation indicates that the structure of the γ-APS layer plays an important role in the promotion and retention of adhesion with a thermoplastic polymer system capable of limited primary interactions through possible interdiffusion with the silane layer.     

Effect of silane treatment parameters on the silane layer formation and bonding to thermoplastic urethane

Enhancing adhesion is of primary importance in preparation of insert injection molded plastic–metal hybrids. Here, the combination of coupling agent application parameters and steel oxide microstructure effects on the adhesion in thermoplastic urethane–stainless steel hybrids was studied. The stainless steel oxide structure was first modified by electrolytical polishing and subsequent oxidation treatment, then the steel was coated with N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (γ-AEAPS) prior to overmolding with thermoplastic urethane. The properties of formed silane coatings and ultimately the thermoplastic urethane–stainless steel hybrids were determined by several microscopical methods, infrared spectroscopy and mechanical testing. The bond strength of hybrids depended on the silane layer thickness. Also the stainless steel surface oxide structure had a remarkable influence on the coating formation and the resulting hybrid bond strength.     

Structure Mechanical Property Changes Occurring in Ethylene Acrylic Acid Copolymer Adhesive During Aging of Bimetallic Laminates

The increase in peel strength after thermal aging of aluminum and copper to tin-plated steel laminates was studied using adhesive samples recovered from copper to tin-plated steel laminates. Morphological changes of the ethylene acrylic acid copolymer adhesive were observed. Calorimetric and dynamic mechanical measurements on adhesive copolymers recovered from Cu-tin plated steel laminates suggest that the crystallinity of EAA increases due to thermal aging as well as oxidative processes. A higher degree of crystallinity and effective crosslink density are consistent with the higher elastic (E') modulus for aged specimens. Increase in crystallinity of an ethylene-acrylic acid copolymer resulted in a higher tensile strength, which appears related to the increase in peel strength of the laminate.     

Interfacial Adhesion of Polyamide 66 Fibres to an Aqueous Polyurethane–Acrylic Hybrid Polymer Adhesive

In this work, the interfacial adhesion between a polyamide 66 fibre, and an aqueous polyurethane–acrylic hybrid polymer adhesive was investigated. Silane and air plasma treatments were introduced to modify the surface of the polyamide 66 fibre. The surface chemistry was characterised using X-ray photoelectron spectroscopy (XPS). There were more oxygen-containing functional groups, –OH or –COOH, introduced by air plasma and silane treatments on the surface of polyamide fibre to increase its chemical activity. The microbond test was used to measure the interfacial shear strength (IFSS) between the waterborne polyurethane–acrylic hybrid polymer adhesive and a polyamide fibre. It has been found that air plasma and silane surface treatments can be used to improve interfacial adhesion. IFSS at 8.7 and 5.9 MPa, respectively, were higher than that of the control, 5.0 MPa. After water immersion at 50°C for 48 h, IFSS dropped to 7.0 MPa for air plasma-treated specimen and to 4.4 and 4.1 MPa for silanised and control specimens, respectively. Air plasma surface treatment is more effective than silane treatment to improve the interface adhesion in the polymer fibre–polymer composite.