Damping of vinyl acetate–n‐butyl acrylate copolymers

A photopolymerization process at room temperature was devised to copolymerize vinyl acetate (VAc) and n‐butyl acrylate (BA) mainly to prepare rubber‐like damping sheet bearing pressure‐sensitive adhesive property in this study. The investigations using both the differential scanning calorimeter and rheometric dynamic analysis show the existence of two glass transition temperatures for each copolymer. The scanning electron microscopic pictures reveal that the degree of microphase separation increases with increasing annealing time at 70°C. It was suggested that the rubbery domain (formed by the PBA blocks) disperses in the glassy domain (constituted by the PVAc blocks), making an effective damping entity. Excellent damping was observed for the copolymer samples, with the tanδ peak values as high as 1.76–1.80 at a certain temperature range and with tanδ> 0.3 at quite wide temperature ranges. In addition, the copolymers containing more VAc tend to have the higher damping. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1396–1403, 2004     

水性丙烯酸酯胶粘剂的合成及性能研究

甲基丙烯酸甲酯、丙烯酸丁酯、丙烯酸为单体,水为溶剂合成了聚丙烯酸酯粘合剂,用DSC、GPC等对产物进行了表征,研究了反应条件、原料配比及用量对产物性能的影响。     

Sustainable isosorbide‐based transparent pressure‐sensitive adhesives for optically clear adhesive and their adhesion performance

A biomass‐based isosorbide acrylate (ISA) was synthesized in a one‐pot reaction at low temperature with a quite slow dropwise technique using a syringe pump. Using the ISA monomer, UV‐cured transparent acrylic pressure‐sensitive adhesives (PSAs) composed of semi‐interpenetrating networks were prepared. The effect of ISA on the adhesion performance of the resulting acrylic PSAs was investigated by changing the ISA content, while fixing the mole ratio between 2‐ethylhexyl acrylate and 2‐hydroxyethyl acrylate in the PSAs. The prepared acrylic PSAs, with ISA content ranging from 3.2 to 14.3 mol%, were evaluated in terms of 180° peel strength, probe tack, static shear testing and optical properties. Increasing the ISA content in the acrylic PSAs improved the adhesion properties, such as 180° peel strength (0.25–0.32 N/25 mm), shear holding power (0.086–0.023 mm) and probe tack (1.21–2.26 N). Dynamic mechanical analysis indicated that ISA is a good candidate monomer, playing the role of adhesion promoter and hard monomer in the acrylic PSAs. © 2017 Society of Chemical Industry     

Synthesis and characterization of N‐acryloylcarbazole/methyl methacrylate copolymers

Copolymers of N‐acryloylcarbazole (A) and methyl methacrylate (M) were synthesized in different in‐feed ratios. The composition of the copolymer was determined by the help of ¹H NMR spectrum. The comonomer reactivity ratios determined by Kelen‐Tudos (KT) and nonlinear error‐in‐variables methods were r_A = 1.12 ± 0.16, r_M = 0.94 ± 0.14, and r_A = 1.05, r_M = 0.90, respectively. Complete spectral assignments of the ¹H and ¹³C ¹H NMR spectra of the copolymers were done by the help of distortionless enhancement by polarization transfer (DEPT) and two‐dimensional NMR techniques, such as heteronuclear single quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple bond correlation (HMBC). The methine, α‐methyl, and carbonyl carbon resonances were found to be sequence sensitive. The signals obtained were broad because of the restricted rotation of bulky carbazole group and the quadrupolar effect of nitrogen present in carbazole moiety. Glass transition temperatures (T_g) were determined by differential scanning calorimetry and were found to be characteristic of copolymer composition. As the N‐acryloylcarbazole content increases, the T_g increases from 378.3 K for poly(methyl methacrylate) to 430.4 K for poly(N‐acryloylcarbazole). Variation in T_g with the copolymer composition were found to be in good agreement with theoretical values obtained from Johnston and Barton equations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2667–2676, 2006     

Synthesis,characterization, and reactivity ratios of copolymers derived from 4‐nitrophenyl acrylate and n‐butyl methacrylate

Free‐radical copolymerization of 4‐nitrophenyl acrylate (NPA) with n‐butyl methacrylate (BMA) was carried out using benzoyl peroxide as an initiator. Seven different mole ratios of NPA and BMA were chosen for this study. The copolymers were characterized by IR, ¹H‐NMR, and ¹³C‐NMR spectral studies. The molecular weights of the copolymers were determined by gel permeation chromatography and the weight‐average (M _w) and the number‐average (M _n) molecular weights of these systems lie in the range of 4.3–5.3 × 10⁴ and 2.6–3.0 × 10⁴, respectively. The reactivity ratios of the monomers in the copolymer were evaluated by Fineman–Ross, Kelen–Tudos, and extended Kelen–Tudos methods. The product of r₁, r₂ lies in the range of 0.734–0.800, which suggests a random arrangement of monomers in the copolymer chain. Thermal decomposition of the polymers occurred in two stages in the temperature range of 165–505°C and the glass transition temperature (T_g) of one of the systems was 97.2°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1817–1824, 2003     

High‐temperature solution polymerization of butyl acrylate/methyl methacrylate: Reactivity ratio estimation

Solution copolymerizations of butyl acrylate/methyl methacrylate in toluene were performed over an expanded temperature range (60–140°C) compared to more typical ranges that do not exceed 80°C. From a large amount of data collected independently at two laboratories, reactivity ratios were estimated at five different temperatures. The reactivity ratios were estimated from low conversion copolymer composition data using both the error‐in‐variables model method and a nonlinear parameter estimation based on the integrated copolymer composition equation. Using all of the available data, temperature‐dependent expressions were developed for the reactivity ratios and compared to previously published bulk copolymerization values. No significant differences appeared to exist between the bulk and solution polymerization reactivity ratios. Furthermore, the copolymer composition data conformed to the Mayo‐Lewis kinetic model over the entire temperature range. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 602–609, 2000     

4‐Acetamidophenyl acrylate copolymers with acrylonitrile and N‐vinyl‐2‐pyrrolidone: Synthesis,characterization, and reactivity ratios

4‐Acetamidophenyl acrylate (APA) was synthesized and characterized by IR, ¹H and ¹³C NMR spectroscopies. Homo‐ and copolymers of APA with acrylonitrile (AN) and N‐vinyl‐2‐pyrrolidone (NVP) were prepared by a free radical polymerization. All the copolymer compositions have been determined by ¹H NMR technique, and the reactivity ratios of the monomer pairs have been evaluated using the linearization methods Fineman–Ross, Kelen–Tudos, and extended Kelen–Tudos. Nonlinear error‐in‐variable model (EVM) method was used to compare the reactivity ratios. The reactivity ratios for copoly(APA–AN) system were APA(r₁) = 0.70 and AN(r₂) = 0.333, and for copoly(APA–NVP) system the values were APA(r₁) = 4.99 and NVP(r₂) = 0.019. Thermal stability and molecular weights of the copolymers are reported. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1919–1927, 2006     

乳液型丙烯酸酯压敏胶粘剂剥离强度的研究

应用正交设计探讨了丙烯酸酯压敏胶粘剂的优化配方，考察了温度、反应时间和单体的滴加速度对共聚反应的影响，并分别用一定量的甲基丙烯酸甲酯、丙三醇和松香对胶粘剂进行了初步改性研究。     

Effects of polymeric emulsifiers on the properties of acrylic emulsion pressure‐sensitive adhesives

A series of polymeric emulsifiers was polymerized with 2‐ethylhexyl acrylate, butyl acrylate, and acrylic acid. The polymeric emulsifiers were used to make emulsion copolymers of 2‐ethylhexyl acrylate, butyl acrylate, and acrylic acid. The average particle size of the synthesized emulsions was around 145 nm and the size distribution was very narrow. Also, the emulsions showed good freeze–thaw stability and adhesion properties. The peel strength and holding power of the emulsions were investigated by changing the composition and molecular weight of the polymeric emulsifier. The results show that the peel strength exhibits a maximum at particular molecular weight and acrylic acid content of the polymeric emulsifier, while the holding power increases with molecular weight. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1456–1460, 2004     

乳液型丙烯酸酯压敏胶的研制

采用乳液聚合制备了乳液型聚丙烯酸酯压敏胶,讨论了软单体的用量、硬单体用量、交联单体的种类及用量、引发剂的用量、交联剂的用量和乳化剂的配比对压敏胶性能的影响。实验表明,在相同的条件下,丙烯酸的改性效果比丙烯酸羟乙酯好,当m（EHA）∶m（VAc）=82∶10时,压敏胶的综合性能最佳。交联剂的加入明显提高了剥离强度,当其质量分数为0.3%时,剥离强度达到357.33 N/m。     

溶剂型丙烯酸酯压敏胶的研制

以甲基丙烯酸甲酯(MMA)和醋酸乙烯酯(VAc)为硬单体、丙烯酸(AA)和丙烯酸羟乙酯(HEA)为交联单体、甲苯-2,4-二异氰酸酯(TDI)为交联剂和偶氮二异丁腈(AIBN)为引发剂,采用溶液聚合法制取溶剂型聚丙烯酸酯压敏胶(PSA),讨论了硬单体和交联单体的种类及用量、引发剂和交联剂的用量以及烘胶温度对PSA性能的影响。实验结果表明,当W(AA)=3%、W(VAc)=17%时,初粘力为13号球,剥离强度达到14.17N/15mm,PSA的综合性能最佳;当W(TDI)=1.2%时,剥离强度(17.26N/15mm)达到最大值;当W(AIBN)=0.5%时,胶液的黏度适中,综合性能最佳。     

Synthesis of removable and repositionable water‐borne pressure‐sensitive adhesive acrylics

This publication shows the synthesis of the water‐borne removable pressure‐sensitive adhesive (PSA) based on acrylates and the influence of parameters such as internal emulsifiers on peel adhesion on steel and also the influence of N‐methylol acrylamide and plasticizers on peel adhesion on glass, poly(vinyl chloride), and polypropylene during aging time. Removable and repositionable pressure‐sensitive adhesives based on acrylic polymers are used for the production of removable memo notes, paper and foil labels, double‐sided tapes, carrier‐free tapes to protective films, and manufacturing aids. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 886–892, 2005     

乳液型丙烯酸酯压敏胶研究进展

针对乳液型丙烯酸酯PSA(压敏胶)的耐水性较差、耐高温性欠佳及涂布干燥速率较慢等弊病,综述了乳液型丙烯酸酯PSA的最新研究方向及进展(包括高固含量乳液型丙烯酸酯PSA、乳液型交联丙烯酸酯PSA、低表面能材料粘接用乳液型丙烯酸酯PSA和耐水性乳液型丙烯酸酯PSA等);最后对其应用前景进行了展望。     

UV curable pressure‐sensitive adhesives for fabricating semiconductors. II. The effect of functionality of acrylate monomers on the adhesive properties

In an attempt to control the adhesive properties of acrylic copolymer‐based pressure‐sensitive adhesives, a series of multifunctional acrylate monomers were added and UV cured. The adhesive compound with a difunctional monomer had increased peel strength after UV curing. On the other hand, the compound with a tri‐ or more functional (polyfunctional) monomer had markedly decreased strength after UV curing. Those adhesives containing any polyfunctional monomer also showed much higher storage modulus than an adhesive containing a difunctional monomer. The greater volume contraction of UV‐cured polyfunctional monomer suggested microvoids at the interface between the adhesive layer and the adherent, resulting in poor strength. Estimated values of the peel strength of UV‐cured adhesives according to the theoretical equations proved that the strength is approximately inversely proportional to the elastic moduli. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2889–2895, 2004     

Synthesis,characterization, and properties of intercalated poly(2‐ethyl hexylacrylate)/silicate nanocomposites: XRD,TEM, IR,TGA, superabsorbency,pressure‐sensitive adhesion,and biodegradation

Poly(2‐ethyl hexylacrylate) (PEHA)/silicate composites were synthesized by the emulsion polymerization of ethyl hexylacrylate (EHA) in the presence of sorbitol and the composites were analyzed to be of nano order. The nanocomposites so prepared were shown to be intercalated by X‐ray diffraction, transmission electron microscopy, and infrared spectroscopy. The thermal stability of the nanocomposites was found to be appreciably increased. These nanocomposites are potentially suitable for novel uses such as pressure‐sensitive adhesives and superabsorbents. The biodegradability and superabsorbency of these nanocomposites were evaluated for their commercial potential. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1007–1011, 2004     

Influence of selected photoinitiators on important properties of photoreactive acrylic pressure‐sensitive adhesives

Photoreactive solvent‐borne pressure‐sensitive adhesives are not commercially available in the market. The reason for it is that the UV‐initiated crosslinking has sense only in the case of solvent‐free self‐adhesive systems. Investigations conducted in Institute of Chemical Organic Technology have shown that the photoreactive solvent‐borne acrylic PSA are conventional crosslinked solvent‐borne acrylic PSA used as crosslinking agents typical metal chelates as titanium acetylacetonate (TiACA), aluminum acetylacetonate (AlACA) or thermal reactive crosslinker melamine‐formaldehyde resin Cymel 303 clear considered. The main purpose of the investigation was to study the influence of diverse photoinitiators on main properties, such as shrinkage, tack, peel adhesion, and shear strength of solvent‐based acrylic pressure‐sensitive adhesives. The interesting alternative to conventional photoinitiators is unsaturated photoinitiators described in this article. Following unsaturated photoinitiators were used: 4‐acryloyloxy benzophenone, 4‐acryloyloxyethoxy benzophenone, and 4‐acryloyloxybutoxy benzophenone. The influence of the crosslinking agents or crosslinking methods was determined in relation to the reaction time and to the concentration versus adhesion properties. The increase of photoinitiator concentration causes in the decrease of the shrinkage. Increasing the UV dose during the crosslinking of acrylic PSA film leads clearly to better shrinkage resistance. The best results of the lowest shrinkage value of 0.35% were given by using 4‐acryloyloxy benzophenone. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Resultant synergism in the shear resistance of acrylic pressure‐sensitive adhesives prepared by emulsion polymerization of n‐butyl acrylate/2‐ethyl hexyl acrylate/acrylic acid

Acrylic emulsion pressure‐sensitive adhesives (PSAs) were synthesized by the copolymerization of n‐butyl acrylate with various levels of 2‐ethyl hexyl acrylate (2EHA) and a small constant amount of acrylic acid. The effect of varying the n‐butyl acrylate/2EHA monomer composition on the kinetic behavior of the polymerization and the characteristics of the copolymers prepared in a batch process were investigated. The results showed that increasing the amount of 2EHA in the monomer caused the polymerization rate and the glass‐transition temperature of the acrylic copolymers to decrease. Increasing the amount of 2EHA caused the gel content of the copolymers to decrease, reaching a minimum at 50 wt %; thereafter, the gel content increased at higher 2EHA levels. For the acrylic emulsion, the peel‐fracture energy of the PSAs decreased as the amount of 2EHA in the monomer was increased up to 50 wt %. At higher 2EHA levels, the peel‐fracture energy was relatively constant. Interestingly, a synergistic effect of increased shear resistance at 25 wt % 2EHA was observed without a significant trade‐off in terms of the peel and tack properties. This behavior was attributed to a good interconnection between the microgels and the free polymer chains inside the contacting particles in the adhesive film. Cooperation between various levels of 2EHA in the copolymer structure simultaneously changed the crosslink molecular weight (M_c) of the microgels and the entanglement molecular weight (M_e) of the free chains in the adhesive network morphology. The adhesive performance of the PSAs was found to be correlated with their M_c/M_e values as the 2EHA proportion was varied. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

丙烯酸酯类低聚物改性水性聚氨酯压敏胶的性能研究

以聚醚多元醇和IPDI(异佛尔酮二异氰酸酯)为主要原料,以自制的DJW-330(丙烯酸酯类低聚物)为WPU(水性聚氨酯)乳液的化学改性剂,采用自乳化法合成了性能良好的改性WPUA(水性聚氨酯丙烯酸酯)乳液。结果表明:当R=n(-NCO)/n(-OH)=0.95、w(DJW-330)=1.4%时,改性WPUA乳液的稳定性较好,其粒径分布变宽,耐热性略高于未改性WPU乳液;由于DJW-330与WPU分子间是以化学键的形式结合,故此时改性WPUA压敏胶的初粘力(14#号球)、持粘力(100 min)和180°剥离强度(5.38 N/cm)同时达到最大值。     

Molecular design for silane‐terminated polyurethane applied to moisture‐curable pressure‐sensitive adhesive

Moisture‐curable silane‐terminated polyurethanes (SPUs) served as pressure‐sensitive adhesive (PSA) were synthesized based on different soft‐segment materials, silanes and silane end‐capping ratios. Depending on peel strength, tack, and holding power, the characteristic properties for PSA, a proper scheme for the design of the PSA molecular structure could be selected. Completely end‐capped by silane and assembled by poly(propylene glycol), SPU films presented better properties. On the basis of comprehensive considerations, the anilinomethyltriethoxysilane was an excellent silane‐end capper for PSA. Otherwise, the obtained PSAs did not degrade below 250 °C. The glass transition temperature and hydrophobicity of SPU samples with different formulas were also investigated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45292.     

Rheological and adhesion properties of acrylic pressure‐sensitive adhesives

Different pressure‐sensitive adhesives (PSAs) based on acrylic monomers were synthesized under different reaction conditions. The synthesized PSAs have good adhesive properties and without leaving any residue can be easily peeled off from the surface of a substrate. The relationship between PSAs rheological behavior and its adhesion properties (e.g., peel, tack, and shear resistance) has been studied at constant adhesive thickness. The samples were examined for their surface energy and viscoelastic characteristics. It was observed that increase in reaction temperature and reaction time results in decreased storage modulus due to lowered molecular weight, which finally leads to lower elasticity of the PSA. While the storage (G′) and loss (G″) modulus of samples increase with increased initiator concentration, the elasticity of PSA is increased as well. High G″ at high frequency (100 Hz) represents high peel strength because of higher dissipation of viscoelastic energy during debonding. The tack values increase by lowering storage modulus at 1 Hz due to higher M_e. Shear values are increased by higher storage modulus at low frequency (0.1 Hz) due to hydrogen bonding of the different components. Some parallel investigations on the surface energy of the samples showed that they have different properties because of the nature of different monomeric units with their corresponding orientations. Our results reveal that the peel strength is not affected by surface energy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011