Adhesion of Triblock Copolymer-Based Thermoreversible Gels and Pressure Sensitive Adhesives

2000 ◽  
Vol 629 ◽  
Author(s):  
Kenneth R. Shull ◽  
Alfred J. Crosby ◽  
Cynthia M. Flanigan

ABSTRACTTriblock copolymers with poly (methyl methacrylate) (PMMA) end blocks and a poly (n-butyl acrylate) (PnBA) midblock have been synthesized as model pressure sensitive adhesives and thermoreversible gels. These materials dissolve in a variety of alcohols at temperatures above 60 °C to form freely flowing liquids. At lower temperatures the PMMA end-blocks associate so that the solutions form ideally elastic solids. In our case the solvent is 2-ethylhexanol, polymer volume fractions vary from 0.05 to 0.3, and the elastic moduli are close to 10,000 Pa. We have conducted three types of experiments to elucidate the origins of adhesion and bulk mechanical properties of these materials: 1) Weakly adhering gels: The adhesive properties of the gels are dominated by the solvent. Very little adhesion hysteresis is observed in this case, although we do observe hysteresis associated with the frictional response of the layers. 2) Strongly adhering gels. By heating the gels in contact with a PMMA surface, it is possible to bond the gels to the surface. Development of adhesion as the PMMA blocks penetrate into the PMMA substrate can be probed in this case. The cohesive strengths of the gels are found to be substantially greater than their elastic moduli, so that these materials can be reversibly extended to very high strains. These properties have enabled us to probe the origins of elastic shape instabilities that play a very important role in the behavior of thin adhesive layers. 3) Dried gels – model pressure sensitive adhesives. By removing the solvent at low temperatures, the underlying structure of the gel is preserved, giving a thin elastic layer with excellent performance as a pressure sensitive adhesive. Resistance to adhesive failure, expressed as a velocity-dependent fracture energy, greatly exceeds the thermodynamic work of adhesion. This energy is further magnified by ‘bulk’ energy dissipation when the stress applied to the adhesive layer exceeds its yield stress.

2000 ◽  
Vol 662 ◽  
Author(s):  
Marc B. Taub ◽  
Reinhold H. Dauskardt

AbstractThe development and implementation of successful transdermal devices for drug delivery requires an understanding of the adhesion occurring between the device and the soft dermal layer. This study utilizes a mechanics approach to quantify the adhesive properties of representative pressure sensitive adhesives (PSAs) used as the adhesive layer in these systems. Debonding of PSAs is accompanied by cavitation in the PSA and the formation of an extensive cohesive zone behind the debond tip. The presence of such large-scale bridging provides significant energy dissipation and increased resistance to delamination. The strain energy release rate (G) during debonding of a cantilever-beam sample, containing at its midline a thin layer of PSA, was utilized to quantify the adhesion of the PSA. The analysis accounts for both the work of adhesion as well as the viscoelastic constitutive behavior of the soft adhesive layer. Effects of strain rate, physiological environment, and permeation-enhancement additions are considered. The resistance of human stratum corneum to debonding between corneocyte layers is also presented, as knowledge of this parameter is essential for developing techniques to test the fracture resistance of the PSA-stratum corneum interface present in the clinical use of these transdermal devices.


2009 ◽  
Vol 11 (3) ◽  
pp. 1-4
Author(s):  
Zbigniew Czech ◽  
Agnieszka Butwin

Butyl acrylate/4-acryloyloxy benzophenone copolymers as photoreactive UV-crosslinkable pressure-sensitive adhesives It has previously been shown that copolymers of butyl acrylate with 4-acryloyloxy benzophenone can be used as pressure-sensitive adhesives (PSAs). This paper presents the synthesis and application of a solvent-borne polymer system for the preparation of photoreactive UV-crosslinkable acrylic pressure-sensitive adhesives. Butyl acrylate/benzophenone copolymers with molecular mass in the range 180 000 to 480 000 Dalton were prepared by carrying out free-radical solution polymerization. These copolymers were found to be tacky but in some cases to possess insufficient cohesive strength after UV-crosslinking to be useful as PSAs. The other copolymers resulted in materials with the balance of cohesive and adhesive characteristics required of good PSAs. Some of the parameters affecting the pressure-sensitive adhesive properties of the copolymers are the concentration of 4-acryloyloxy benzophenone, the molecular mass of the polymeric components, the UV-reactivity, and properties such as tack, peel adhesion, and cohesion.


Author(s):  
Liliane Léger ◽  
Costantino Creton

Based on several significant examples, we analyse the adhesion mechanisms at soft polymer interfaces with a special emphasis first on the role of connector molecules, that is, polymer chains bound to the interface and which transmit stress through a stretching and extraction mechanism, and second on the necessary relay that must be taken by additional dissipation mechanisms acting at larger scales if one wants to reach typical fracture toughnesses in the range of a few 10 J m −2 . Examples of such bulk dissipation mechanisms will be discussed for interfaces between polymer melts and for pressure-sensitive adhesives in contact with a solid surface. We shall particularly point out the fact that the level of adhesion results from a competition between adhesive failure usually driven by both the interactions and the friction properties of the interface and bulk strong deformations which take place in the bulk of the adhesive layer. Controlling the friction properties of the interface then becomes a tool to finely tune adhesive properties.


Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 975
Author(s):  
Ehsan Mehravar ◽  
Michael Gross ◽  
Gracia Leal ◽  
Bernd Reck ◽  
Jose Leiza ◽  
...  

A waterborne pressure-sensitive adhesive (PSA) that shows high adhesive performance and easy debondability on demand without leaving residues on the substrate (adhesive failure) has been developed. A key component of the PSA is a semicrystalline phase that is beneficial for the adhesive properties and that becomes fluid when heated above the melting temperature. Migration of this liquid-like polymer to the substrate-adhesive interface and hardening upon cooling results in a hard non-tacky interface that facilitates debonding. The effect of the particle morphology on the debonding ability is discussed.


Author(s):  
Zbigniew Czech ◽  
Dominika Sowa ◽  
Jagoda Kowalska

The manuscript describes synthesized of photoreactive UV-crosslinkable solvent-borne acrylic pressure-sensitive adhesives (PSA) based on butyl acrylate (BA) and copolymerizable photoinitiator 4-acryloyloxy benzophenone (ABP) characterized by molecular mass in the range of 180 000 to 480 000 Dalton. These copolymers were tacky but possessed insufficient cohesive strength after UV-crosslinking to be useful as PSA. They resulted in materials having a balance of cohesive and adhesive characteristics required of good PSA. Some of the parameters affecting the pressure-sensitive adhesive properties of the copolymer are: amount of the 4-acryloyloxy benzophenone, molecular mass of the polymeric components, UV-reactivity and such important properties like tack, peel adhesion and shear strength.


TAPPI Journal ◽  
2016 ◽  
Vol 15 (10) ◽  
pp. 631-639
Author(s):  
MOHAMMAD HADI ARYAIE MONFARED ◽  
HOSSEIN RESALATI ◽  
ALI GHASEMIAN ◽  
MARTIN A. HUBBE

This study investigated the addition of acrylic fiber to old corrugated container (OCC) pulp as a possible means of overcoming adverse effects of water-based pressure sensitive adhesives during manufacture of paper or paperboard. Such adhesives can constitute a main source of stickies, which hurt the efficiency of the papermaking process and make tacky spots in the product. The highest amount of acrylic fiber added to recycled pulps generally resulted in a 77% reduction in accepted pulp microstickies. The addition of acrylic fibers also increased pulp freeness, tear index, burst strength, and breaking length, though there was a reduction in screen yield. Hence, in addition to controlling the adverse effects of stickies, the addition of acrylic fibers resulted in the improvement of the mechanical properties of paper compared with a control sample.


Soft Matter ◽  
2018 ◽  
Vol 14 (47) ◽  
pp. 9681-9692 ◽  
Author(s):  
Chung-Yuen Hui ◽  
Zezhou Liu ◽  
Helen Minsky ◽  
Costantino Creton ◽  
Matteo Ciccotti

The common pressure sensitive adhesive (PSA) tape is a composite consisting of a stiff backing layer and a soft adhesive layer.


2007 ◽  
Vol 9 (2) ◽  
pp. 5-9 ◽  
Author(s):  
Roland Milker ◽  
Zbigniew Czech ◽  
Marta Wesołowska

Synthesis of photoreactive solvent-free acrylic pressure-sensitive adhesives in the recovered system The present paper discloses a novel photoreactive solvent-free acrylic pressure-sensitive adhesive (PSA) systems, especially suitable for the so much adhesive film applications as the double-sided, single-sided or carrier-free technical tapes, self-adhesive labels, protective films, marking and sign films and wide range of medical products. The novel photoreactive solvent-free pressure-sensitive adhesives contain no volatile organic compounds (residue monomers or organic solvent) and comply with the environment and legislation. The synthesis of this new type of acrylic PSA is conducted in common practice by solvent polymerisation. After the organic solvent are removed, there remains a non-volatile, solvent-free highly viscous material, which can be processed on a hot-melt coating machine at the temperatures of about 100 to 140°C.


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