Properties Of Pressure-sensitive Adhesives Research Articles

Low modulus hydrogel-like elastomer sensors with ultra-fast self-healing, underwater self-adhesion, high durability/stability and recyclability for bioelectronics

Flexible sensors simultaneously with property of hydrogel-like low modulus/room temperature ultra-fast self-healing and with elastomer-like durability /environmental stability and underwater adhesion for bioelectronics has not been reported. A low modulus hydrogel-like elastomer that achieves ultrafast self-healing through molecular chain entanglement at room temperature was prepared based on furfuryl alcohol-modified poly(sebacate glyceride) (PGS) prepolymer, furfuryl alcohol-modified poly(ionic liquid) and bismaleimide by Diels-Alder (DA) reaction. The conductive elastomer-based flexible sensors exhibit hydrogel-like properties of low modulus (6.41 kPa) and ultra-fast self-healing (98 % self-healing efficiency within 5 s). The elastomer also possesses rapid subzero and underwater self-healing properties within 5 s. Moreover, PGS-0.2DA-0.2PIL exhibits pressure sensitive adhesive properties and can be adhered/re-adhered in water. The flexible sensor shows elastomer-like high durability, high environmental stability, multiple recyclability and reusability, and it exhibits wide detection ranges, fast response time, low hysteresis, anti-freezing, anti-bacterial and good biocompatibility. The flexible sensors can accurately identify micro-expressions/eye rotation, monitor human movement/health, detect ECG/EMG signals and control robotic arm movements. In conclusion, a new strategy for design of hydrogel-like conductive elastomers via molecular structure design is proposed, and the elastomers-based flexible sensors with low modulus, rapid self-healing and durability/environmental stability show great promising for bioelectronic applications.

A Pressure-Sensitive, Repositionable Bioadhesive for Instant, Atraumatic Surgical Application on Internal Organs.

Pressure-sensitive adhesives are widely utilized due to their instant and reversible adhesion to various dry substrates. Though offering intuitive and robust attachment of medical devices on skin, currently available clinical pressure-sensitive adhesives do not attach to internal organs, mainly due to the presence of interfacial water on the tissue surface that acts as a barrier to adhesion. In this work, a pressure-sensitive, repositionable bioadhesive (PSB) that adheres to internal organs by synergistically combining the characteristic viscoelastic properties of pressure-sensitive adhesives and the interfacial behavior of hydrogel bioadhesives, is introduced. Composed of a viscoelastic copolymer, the PSB absorbs interfacial water to enable instant adhesion on wet internal organs, such as the heart and lungs, and removal after use without causing any tissue damage. The PSB's capabilities in diverse on-demand surgical and analytical scenarios including tissue stabilization of soft organs and the integration of bioelectronic devices in rat and porcine models, are demonstrated.

Revealing the Impact of Viscoelastic Characteristics on Performance Parameters of UV-Crosslinked Hotmelt Pressure-Sensitive Adhesives: Insights from Time-Temperature Superposition Analysis.

This study emphasizes the influential role of rheology in decoding the viscoelastic properties of pressure-sensitive adhesives (PSAs) vital to predicting key application features such as shear, tack, and peel, depending on the flow characteristics of PSAs during bonding and debonding processes. By applying the principle of time-temperature superposition (TTS), we extend the scope of our frequency analysis, surpassing the technical constraints of the available apparatus. Our exploration aims to uncover the general correlations between PSAs' viscoelastic properties and their performance in end-use applications. Initially, the adhesive performance and viscoelastic properties of a UV-crosslinkable styrene-butadiene-styrene (SBS) model adhesive prior and subsequent to UV irradiation were examined. The subsequent crosslinking reaction increased cohesive strength and heat resistance, although tack and peel strength observed a substantial decline. We successfully demonstrated these effects by logging the viscoelastic properties, specifically the storage modulus G' at lower frequencies, which mirrors the shear strength at higher temperatures and the shift in the tan δ peak to represent each PSA's tack. These correlations were partially reflected in three commercial UV crosslinkable acrylic PSA products, although the effect of UV irradiation was less distinctive. This study also revealed the challenges in predicting tack and peel strength, which result from a complex interplay of bonding and debonding processes. Our findings reinforce the necessity for more sophisticated analysis techniques and models that can accurately predict the end-use performance of PSAs across different physical structures and chemical compositions. Further research is needed to develop these predictive models, which may reduce the need for labor-intensive testing under real-life conditions.

The effect of neat and modified montmorillonite on thermal properties of silicone pressure-sensitive adhesives

Novel silicone pressure-sensitive adhesives containing modified montmorillonite were obtained, and subsequently, one-sided tapes were prepared. The novel adhesives were characterized by a higher tack, peel adhesion, and cohesion at room and elevated temperature when compared to the system without the filler. Adding modified fillers allowed to improve the thermal resistance of adhesive - the maximum operating temperature was in a range of 220–230 °C. The highest level of thermal resistance was obtained for acid-modified montmorillonite with a concentration of 0.1 M. It was found that the physical modification of silicone pressure-sensitive adhesives shifts the adhesive-cohesive balance towards cohesion.

The Effect of Pt-type Catalysts on Self-adhesive Properties of Silicone Pressure-sensitive Adhesives

AbstractUseful silicone pressure-sensitive adhesives (PSAs) have been prepared from a high solid silicone resin. Platinum catalysts and crosslinking compounds were used to obtain new self-adhesive tapes. The influence of catalysts and crosslinking compounds on the basic properties of self-adhesive tapes was tested, taking into account the compatibility of silicone composition. The obtained systems showed good self-adhesive properties, and high thermal resistance over 225 °C. The low viscosity of the compositions obtained relatively increases the application potential of self-adhesive tapes based on it. Moreover, the prepared compositions show the potential for further modifications, especially physical ones e.g. silicon powder. The obtained new tapes showed good self-adhesive properties and kept high thermal resistance over 225 °C. It is well known that silicone pressure-sensitive adhesives are a group of silicone adhesives for special applications. Due to their unique resistance to environmental conditions, temperature and chemical resistance, they are difficult to modify.

Comparison of Aging Simulation to Real Aging of Silicone Self-adhesives Tapes

The paper presents a comparison of the aging of silicone self-adhesive tapes in real conditions and accelerated aging in laboratory conditions. In order to check the correlation between the tested tapes, the tapes were tested immediately 24 h after making and after aging to determine changes in values functional properties such as adhesion, cohesion and tack. The tapes were manufactured on the basis of a selected pressure-sensitive silicone adhesive, which were cross-linked after adding the cross-linker and different dye content. As a result of the compared simulation in the test chamber (accelerated aging) and 7 years aging test, values of useful properties (e.g. adhesion) were obtained similarly. In the presented work, the influence of the amount of dye on the properties of pressure-sensitive adhesives was also examined, which allowed to obtain samples with similar functional properties, easy to compare with each other. The samples together with the dye and the cross-linking compound were subjected to artificial conditions in the chamber (artificial aging) and stored for 7 years.

Influence of diatomite and its base modifications on the self-adhesive properties of silicone pressure-sensitive adhesives

The study examined how diatomite and its modifications affected the self-adhesive ability of silicone pressure-sensitive adhesives. To create adhesive composition for testing, fillers were added to a commercial silicone resin, which were then used to create new modified pressure-sensitive tapes. The resulting tapes were tested to determine their adhesion, tack, cohesion at room and elevated temperature, SAFT test (Shear Adhesive Failure Temperature), pot-life (viscosity) and shrinkage. The results obtained were compared with those of the unmodified tapes. The tests resulted in higher thermal resistance (225 °C) and lower shrinkage (0.1%). As a result, we can conclude that materials with thermal resistance with a slight decrease in other parameters were obtained.

Influence of Illite and Its Amine Modifications on the Self-Adhesive Properties of Silicone Pressure-Sensitive Adhesives.

Obtaining new silicone self-adhesive in the presence of modified illite has been described. The filler was modified with N,N,4-trimethylaniline. The effect of illite content and modification on functional properties (adhesion, cohesion, stickiness, and shrinkage) was determined. Additionally, the thermal resistance (the SAFT test) of obtained silicone pressure-sensitive adhesives was evaluated. For all the systems tested, an increase in thermal resistance and shrinkage decrease were noted. Moreover, only a slight adhesion and tack decrease was revealed. Such self-adhesives could be applied for joining elements operating at increased temperatures, e.g., in heavy industry.

Influence of UV on the self-adhesive properties of silicone pressure-sensitive adhesives

The paper presents the results of research on the UV radiation influence on the self-adhesive properties of silicone adhesives. The adhesives were obtained by cross-linking commercial resins (PSA 590, Q2-7566) at the temperature of 110°C, using different amounts (0–3 wt%) of bis(2,4-dichlorobenzoyl) peroxide. Self-adhesive properties of adhesives such as adhesion, tack, and durability before and after aging were determined. The adhesives showed stable self-adhesive properties, however, the PSA 590 adhesive had a higher maximum operating temperature than the Q2-7566 adhesive.

Influence of Nanoclay on the Thermo-Mechanical Properties of Silicone Pressure-Sensitive Adhesives.

This research was carried on newly obtained innovative materials-self-adhesive one-sided tapes based on silicone pressure-sensitive adhesives. In order to obtain tapes, the stable adhesive composition was subjected to physical modification by incorporating into it various amounts of selected silicon fillers. The produced pressure-sensitive adhesives were tested for viscosity and thermogravimetric analysis, as well as the manufactured tapes; i.e., peel adhesion, tack, cohesion at room and elevated temperature, SAFT test (shear adhesive failure temperature), and shrinkage. The prepared self-adhesive tapes retained their self-adhesive properties at a level close to the initial level while increasing the thermal resistance by 70-75 °C, reaching the level of 220-225 °C. The new self-adhesive materials have application potential and can be used as a material for special applications in the field of electrical engineering and heavy industry.

Influence of storage time on the useful properties of silicone pressure-sensitive adhesives

The influence of the storage time on the useful properties (cohesion, adhesion, stickiness) of silicone pressure-sensitive tapes (Si-PSA) was investigated. Two types of silicone resins PSA 529 and PSA 590 (Momentive, USA) were used and crosslinked with bis (2,4-dichlorobenzoyl) peroxide (DClBPO). There was no significant effect of tapes long-term storage (7 years) on their properties. The tapes based on PSA 590 resin were more resistant to aging than PSA 529.

Influence of Silicone Additives on the Properties of Pressure-Sensitive Adhesives.

Research was carried out on the influence of various silicone compounds on the properties of pressure-sensitive adhesives. Silicone-based pressure-sensitive adhesives have good self-adhesive properties and are used in many different industries. However, their thermal resistance is relatively low. In order to improve this property, modifications were made to these adhesives. Compositions were tested, such as viscosity or thermogravimetric analysis, as well as tests of finished products in the form of self-adhesive tapes, i.e., peel adhesion, tack, cohesion at room and elevated temperature, SAFT test (Shear Adhesive Failure Temperature), pot-live (viscosity) and shrinkage. During the tests, an increase in thermal resistance (225 °C), lower shrinkage (0.08%), and lower viscosity was achieved (16.5 Pas), which is a positive phenomenon in the technology of pressure-sensitive adhesives. Thanks to this research, the properties of silicone self-adhesive adhesives have been significantly improved.

Macromol. React. Eng. 3/2022

Macromolecular Reaction EngineeringVolume 16, Issue 3 2270005 Cover PictureFree Access Macromol. React. Eng. 3/2022 First published: 16 June 2022 https://doi.org/10.1002/mren.202270005AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Front Cover: Carboxylated cellulose nanocrystals (cCNCs) are used to enhance latex-based pressure-sensitive adhesive (PSA) properties. AFM imaging reveals that cCNCs interact with latex particles and each other; thus, omitting ultrasonication at the preparation stage preserves these interactions and leads to greater property enhancements. The research demonstrates how cCNCs provide superior, fibril-like reinforcements to PSA films without the technical challenges associated with producing composites with nanofibrils. This is reported by Marc A. Dubé and co-workers in article number 2100051. Volume16, Issue3Special Issue: Green Macromolecular Reaction EngineeringJune 20222270005 RelatedInformation

Influence of modified attapulgite on silicone pressure-sensitive adhesives properties

Influence of modified attapulgite on silicone pressure-sensitive adhesives properties

Influence of cleaned granite dust on the properties of silicone pressure-sensitive adhesives

The influence of addition cleaned granite dust on self-adhesive products, such as self-adhesive tapes based on silicone pressure-sensitive adhesives was presented. The new way of waste management, is a very important issue in the modern world. The obtained self-adhesive materials were tested both in terms of the properties of adhesive compositions (pot-life test) as well as the influence on the operational parameters of the obtained self-adhesive tapes, such as adhesion, cohesion, stickiness or shrinkage. The obtained results are presented in the paper below.

Influence of Acrylonitrile Content on the Adhesive Properties of Water-Based Acrylic Pressure-Sensitive Adhesives.

A series of pressure-sensitive adhesives (PSA) were prepared by emulsion polymerization in order to obtain a PSA that meet with the current label market requirements. For it, the effect of the incorporation of acrylonitrile (ACN) as hard monomer was investigated in a n-butyl acrylate (n-BA) and acrylic acid (AA) system. Great differences were found in the adhesive performance according to the ACN weight ratio. Its increased resulted in a considerable rise in the average sol molecular weight and in the glass transition temperature. This was reflected in a decrease of adhesion forces (peel resistance and tack) and an increase of the cohesion forces (shear resistance). Moreover, the incorporation of the minimum amount of ACN studied showed a great change in the elastic modulus determined by dynamic shear resistance with respect to the based formulation that did not contain ACN. Finally, the ice bucket test was carried out to check the adhesive performance in cold and wet environments.

Chemically recyclable polyesters from CO2, H2, and 1,3-butadiene

Chemically recyclable solid polymeric materials with commercializable properties only using CO2 and inexpensive bulk chemicals as chemical feedstock can open a brand-new avenue to economically viable, large-scale fixation of CO2 over a long period of time. Despite previous great advancements, development of such a kind of CO2-based polymers remains a long-term unsolved research challenge of great significance. Herein, we reported the first methodology to polymerize six-membered lactone with two substituents vicinal to the ester group (HL), a compound previously found to be non-polymerizable. The present methodology enables the first synthesis of chemically recyclable solid polyesters (polyHL) with a high CO2 content (28 wt %) and large molecular weights (Mn up to 613.8 kg mol−1). Transparent membranes with promising pressure-sensitive adhesive (PSA) properties comparable with their commercial counterparts can be conveniently fabricated from the polyesters. Mechanistic studies indicate that rigorous removal of water impurity is the key to the successful polymerization of the relatively inert disubstituted six-membered lactone. A complete monomer recovery from polyHL was also successfully achieved under mild catalytic conditions. The synthesis of polyHL only requires CO2 and two inexpensive bulk chemicals, H2 and 1,3-butadiene, as the starting materials, thus providing a new strategy for potential scalable chemical utilization of CO2 with desirable economic values and concomitant mitigation of CO2 emissions. This work should inspire future research to make useful new solid CO2-based polymers that can meaningfully increase the scale of chemical utilization of CO2 and promote the contribution of chemical utilization of CO2 to global mitigation of CO2 emissions.

Sticking Effect of a Tackifier on the Fibrillation of Acrylic Pressure-Sensitive Adhesives.

In this study, the effect of a tackifier on the viscoelastic and adhesion properties of acrylic pressure-sensitive adhesives (PSAs) was investigated. The intermediate products in the process of PSA synthesis, including an acrylate-based copolymer solution, a cross-linked copolymer, and the final product with a tackifier, were prepared and characterized using dynamic mechanical analysis (DMA). A significant increase in storage and loss moduli at high angular velocities was observed for the final product with the tackifier. The adhesion forces of the copolymer solution and the cross-linked copolymer measured by atomic force microscopy (AFM) were found to be almost independent of the release velocity, whereas that of the final product with the tackifier significantly increased at higher release velocities because of viscoelastic effects. Their fibrillations during the release process were also visualized using a charge-coupled device (CCD) camera installed on the cantilever holder. Although the contact area of the copolymer solution and the cross-linked copolymer with the probe surface decreased until detachment, the final product with the tackifier remained constant, with necking just below the probe surface. The increased storage and loss moduli were considered to resist the shrinkage of the contact area because the contact outline was subject to high shearing deformation, which led to localized high strain rates. Overall, the crucial role of the tackifier in maintaining the contact area for sufficient elongation during fibrillation was established.

Improved adhesion properties of natural rubber-based pressure-sensitive adhesives by incorporating particulate fillers

A new concept of producing natural rubber (NR) based pressure-sensitive adhesive (PSA) using solid particles relatively at a low-cost as tack enhancer has been proposed. The effect of tack enhancer (i.e., xyloglucan (XG), rice flour (RF), calcium carbonate (CaCO3), and silica (SiO2)) on the adhesion properties of the PSA was investigated. Moreover, stress relaxation, tan δ, initial plasticity (Po), and molecular weight of NR which relates to the adhesion properties were also determined. The study found that XG, RF, and SiO2 can be used as tack enhancers for NR-based PSA. The obtained PSA from those tack enhancers can adhere and peel off on a polypropylene (PP) substrate without any adhesive residue. An increase in the adhesion properties of NR-based PSA can be explained by the effect of fillers on the viscoelastic properties and molecular weight of the PSA. Stress relaxation and molecular weight of the NR-based PSA were significantly found to be decreased, while the tan δ was increased by the addition of particulate tack enhancers compared to the masticated neat NR. NR-based PSA with the highest peel strength (2.11 × 102 N/m) was successfully developed by using XG (40 phr). The NR-based PSA with XG was also showed the ability to resist the unfavorable aged hardening of the NR-based PSA in 180 days.

Influence of unsaturated photoinitiators on acrylic pressure-sensitive adhesive properties

Solvent-based acrylic pressure-sensitive adhesives (PSAs) containing unsaturated copolymerizable photoinitiators were synthesized. This study describes novel photoreactive acrylic PSAs in which performance in the form of molecular weight, tack, peel adhesion and shear strength are dependent on photoinitiator kind and concentration, UV-dose, and UV-crosslinking time.