• Journal of Adhesion and Interface
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• v.16 no.2
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• pp.55-62
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• 2015

It was investigated that the effect of surface modification and concentration of fumed silica on the adhesion properties and thermal stability of 2-EHA/AA pressure sensitive adhesive (PSAs) prepared by UV irradiation. The influence of repeating units of crosslinking agent on PSAs were also studied. From SEM analysis, PSAs synthesized with surface modified silica had finer dispersion of silica particles in polymer matrix due to the interfacial interaction. Results of the study showed that increase in tack and peel strength when under 0.3 wt% of silane treated silica were added in the reaction mixture. The addition of PEGDMA for crosslinking agent offers positive effect on adhesion properties in comparison with PSAs using EGDMA for crosslinker, which may be attributed to high mobility of ethylene oxide repeating units in PEGDMA. From the thermal degradation residue of PSAs, it was revealed that thermal stability was improved with silica addition due to the strong interfacial bonding between silane modified silica and polymer matrix, which may act as a thermal barriers into 2-EHA/AA PSAs.

• Elastomers and Composites
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• v.43 no.2
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• pp.82-87
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• 2008

In this study, nine kinds of polyimides were synthesized from 1,2,4,5-benzenetetracarboxylic dianhydride (PMDA), 4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA), m-pheny lenediamine (m-PDA) and 4,4'-oxydianiline (ODA) by controlling molar ratio of monomers. Synthesized polyimides were used as insulator films for 2-layer Flexible Copper Clad Laminate(FCCL) which were manufactured by the casting method. Glass transition temperature and thermal degradation temperature for 5% weight loss of the polyimide film were improved by increasing contents of m-PDA and PMDA, respectively. Water absorption of polyimide film was reduced by increasing contents of ODA and BPADA which have relatively long structure, respectively. Peel strength of 2-layer FCCL was improved by increasing contents of ODA and BPADA.

• Polymer(Korea)
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• v.38 no.5
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• pp.682-686
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• 2014

To prepare transparent acrylic pressure sensitive adhesives (PSAs), terpolymer syrups were photopolymerized from 2- ethylhexyl acrylate and 2-hydroxyethyl acrylate with third monomer having different chemical structure. After polymerization, 1,6-hexanediol diacrylate as a crosslinker and a photoinitiator were added and then UV-irradiated to prepare the PSAs. The adhesion performances and optical characteristics of the PSAs were investigated. Their adhesion performance was dependent on the composition of monomers in the polymer chain but optical properties were maintained at a suitable level. The PSAs prepared by bulky and heteroatom-containing monomers such as IBOA, THFA, and ACMO showed better adhesion performance than others.

• Elastomers and Composites
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• v.44 no.4
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• pp.429-435
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• 2009

The pressure sensitive adhesives (PSA) were synthesized by soap-free emulsion polymerization of acrylic monomers such as butyl acrylate, 2-ethyl hexyl acrylate, and acrylic acid in the presence of starch as a protective colloid and copolymer. The peel strength and holding power of PSA were increased with starch contents due to the enhancement of gel content, But the initial tackiness of PSA was decreased with starch contents. The contact angle analysis of PSA indicated that the wettability was increased with starch contents owing to the increase of polarity by hydroxy group in starch. In the pH measurement of emulsion with time for biodegradability, the starch in the PSA accelerated the lowering of pH due to the formation of organic acids followed by decomposition of starch.

• Elastomers and Composites
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• v.49 no.3
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• pp.210-219
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• 2014

In this study, the acrylic pressure sensitive adhesive (PSA) for the optical functionality sheet was prepared by blending liquid isoprene rubber. The acrylic PSA was synthesized with butyl acrylate, acrylic acid, 2-ethylhexyl acrylate and 2-hydroxyethyl methacrylate. Toluene was used to a solvent for polymerization. Liquid isoprene rubber (LIR-50) was blended with the acrylic PSA and blend ratio was 0 ~ 50 wt%. According to the results, the adhesive transfer, which was the big problem of acrylic adhesive, was reduced with the addition of LIR-50. The secondary bonding of LIR-50 with substrate did not occurred due to absence of polar group in LIR-50. The peel strength and adhesive transfer were decreased by UV curing and the degreed of decrease depended on the amounts of photoinitiator and UV irradiation time. On the other hand holding power increased drastically by increasing amounts of photoinitiator and UV irradiation time.

• Elastomers and Composites
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• v.49 no.3
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• pp.199-203
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• 2014

Terpolymer syrups were photopolymerized from 2-ethylhexyl acrylate, 2-hydroxylethyl acrylate and isobornyl acrylate to prepare acrylic pressure sensitive adhesives (PSAs). After polymerization, various crosslinkers as 1,6-hexanediol diacrylate (HDDA), poly (ethylene glycol) diacrylate (PEGDA, Mn = 250, 575, and 700) were added and then UV-irradiated to prepare the semi-IPN type PSAs. Their adhesion performance and storage modulus (G') were strongly dependent on their chemical structure and molecular weight of the crosslinkers. Optical properties such as transmittance (> 92.5 %), haze (< 1.0 %) and color-difference (< 0.3) of PSAs samples were not affected by crosslinker types used in this study.

• Journal of the Korean Solar Energy Society
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• v.38 no.1
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• pp.45-55
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• 2018

Environmentally benign lead-free solder coated ribbon (e. g. SnCu, SnZn, SnBi${\cdots}$) has been intensively studied to interconnect cells without lead mixed ribbon (e. g. SnPb) in the crystalline silicon(c-Si) photovoltaic modules. However, high melting point (> $200^{\circ}C$) of non-lead based solder provokes increased thermo-mechanical stress during its soldering process, which causes early degradation of PV module with it. Hence, we proposed low-temperature conductive paste (CP) based tabbing method for lead-free ribbon. Modules, interconnected by the lead-free solder (SnCu) employing CP approach, exhibits similar output without increased resistivity losses at initial condition, in comparison with traditional high temperature soldering method. Moreover, 400 cycles (2,000 hour) of thermal cycle test reveals that the module integrated by CP approach withstands thermo-mechanical stress. Furthermore, this approach guarantees strong mechanical adhesion (peel strength of ~ 2 N) between cell and lead-free ribbons. Therefore, the CP based tabbing process for lead free ribbons enables to interconnect cells in c-Si PV module, without deteriorating its performance.

• Journal of Adhesion and Interface
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• v.12 no.2
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• pp.62-66
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• 2011

In this study, we synthesized a excellent adhesive chlorinated polyolefin (CPO)-g-$\beta$-carboxy ethyl acid ($\beta$-CEA) by radical polymerization. Also, we prepared low-level toxic primer for polypropylene (PP) using CPO-g-$\beta$-CEA and studied toxic and adhesion property. We identified the graft structure and properties of the prepared chlorinated polyolefin-g-$\beta$ CEA using FT-IR, DSC, UTM. Graft ratio were optimum value at 5 wt% $\beta$-CEA contents in CPO-g-$\beta$ CEA. And the primer for PP was prepared with CPO-g-$\beta$ CEA and adhesive builder PX-95 content. Finally, optimum peel strength obtained when PX-95 contents was 3 wt%.

• Journal of Adhesion and Interface
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• v.8 no.4
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• pp.1-7
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• 2007

Waterborne polyurethane (WPU) which is environment friendly has been rapidly used in coating and adhesive industries. However, the WPU is deficient in chemical resistance, thermal resistance, and mechanical property compared to solvent-based polyurethane. In this study, the WPU was synthesized from two types of polyester polyols, 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$), dimethylolpropionic acid (DMPA), triethylamine (TEA) and ethylenediamine (EDA), organophilic nanoclay. The thermal stability, mechanical property of the WPU nanocomposite dispersion increased with increasing clay concentration. Especially, their peel strength showed their maximum value at 3 wt% of organophilic nanoclay contents.

• Journal of Adhesion and Interface
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• v.23 no.3
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• pp.80-86
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• 2022

In this study, water-based acrylic tackifier with different contents of 1-dodecanethiol(n-DM), a chain transfer agent(CTA), were synthesized to improve the performance and adhesive properties of water-based acrylic pressure sensitive adhesive(PSA). In order to investigate the change in physical properties according to the amount of water-based acrylic tackifier added, 10/20/30 phr of water-based acrylic tackifier was added to the water-borne acrylic emulsion to measure the physical properties. The molecular weight and glass transition temperature(T_g) of the synthesized water-based acrylic tackifier tended to decrease as the content of n-DM increased. When a water-based acrylic tackifier was added to the water-borne acrylic emulsion, the peel strength and heat-resistance were increased. Also, when the water-based acrylic tackifiers were added at 10 phr or 20 phr, the best value was shown.