Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Aug 13;14(16):4563.
doi: 10.3390/ma14164563.

The Effect of Type-I Photoinitiators on the Kinetics of the UV-Induced Cotelomerization Process of Acrylate Monomers and Properties of Obtained Pressure-Sensitive Adhesives

Agnieszka Kowalczyk  1 , Mateusz Weisbrodt  1 , Beata Schmidt  1 , Agata Kraśkiewicz  1
Affiliations

The Effect of Type-I Photoinitiators on the Kinetics of the UV-Induced Cotelomerization Process of Acrylate Monomers and Properties of Obtained Pressure-Sensitive Adhesives

Agnieszka Kowalczyk et al. Materials (Basel). .

Abstract

A new method of solvent-free acrylic pressure-sensitive adhesives (PSAs) based on UV-induced cotelomerization products was presented. The key acrylic monomers (i.e., n-butyl acrylate and acrylic acid) with copolymerizable photoinitiator 4-acrylooxybenzophenone in the presence of a selected chain transfer agent (tetrabromomethane, TBM) were used in the UV-cotelomerization process. Moreover, two kinds of UV-photoinitiators (α-hydroxyalkylphenones, HPs and acylphosphine oxides, APOs) were tested. Photo-DSC, viscosity, thermogravimetric, and GPC measurements for cotelomers were performed. The kinetics study revealed that the systems with APOs, especially Omnirad 819 and Omnirad TPO, were characterized by a much higher reaction rate and greater initiation efficiency than HPs systems were. Additionally, the APO-based syrups exhibited a higher solid content (ca. 60-96 wt%), a higher dynamic viscosity (5-185 Pa·s), but slightly lower molecular weights (Mn and Mw) compared to HP syrups. However, better self-adhesive features (i.e., adhesion and tack) were observed for PSAs based on cotelomers syrups obtained using APOs with lower solid contents (55-80 wt%). It was found that as the solids content (i.e., monomers conversion) increased the adhesion, the tack and glass transition temperature decreased and the type and amount of photoinitiator had no effect on polydispersity. Most of the obtained PSAs were characterized by excellent cohesion, both at 20 °C and 70 °C.

Keywords: acrylic syrups; adhesion; bulk photopolymerization; pressure-sensitive adhesives; radical photoinitiators; telomerization.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Schematic graph of UV-induced cotelomerization process with different type I radical photoinitiators.
Figure 2
Figure 2
Preparation steps of the pressure-sensitive adhesives from BAA cotelomers.
Figure 3
Figure 3
Kinetics parameters of BA, AA, and ABP photo-cotelomerization process in the presence of TBM as a chain transfer agent (I0 = 15 mW/cm2; 320–390 nm); Rp—reaction rate; p—conversion of double bonds.
Figure 3
Figure 3
Kinetics parameters of BA, AA, and ABP photo-cotelomerization process in the presence of TBM as a chain transfer agent (I0 = 15 mW/cm2; 320–390 nm); Rp—reaction rate; p—conversion of double bonds.
Figure 4
Figure 4
Initiation efficiency (Ip) of the radical photoinitiators used for photo-cotelomerization processes of BA, AA, and ABP with TBM.
Figure 5
Figure 5
Viscosity (a) and solid content (b) of obtained BAA syrups.
Figure 6
Figure 6
Dependence of adhesion to steel and solid content on photoinitiator concentration.
Figure 7
Figure 7
Adhesion to steel of PSA based on BAA cotelomers prepared using different types and concentrations of PIs.
Figure 8
Figure 8
Tg values of PSAs based on BAA cotelomer.
See this image and copyright information in PMC

References

    1. Slota J., Kubit A., Trzepieciński T., Krasowski B., Varga J. Ultimate Load-Carrying Ability of Rib-Stiffened 2024-T3 and 7075-T6 Aluminium Alloy Panels under Axial Compression. Materials. 2021;14:1176. doi: 10.3390/ma14051176. - DOI - PMC - PubMed
    1. Satas D. Handbook of Pressure Sensitive Adhesive Technology. Springer; Warwick, RI, USA: 1999. pp. 346–398.
    1. Creton C. Pressure-Sensitive Adhesives: An Introductory Course. MRS Bull. 2003;28:434–439. doi: 10.1557/mrs2003.124. - DOI
    1. Brockmann W., Geiss P., Klingen J., Schröder B. Adhesive Bonding: Materials, Applications and Technology. Wiley-VCH Verlag GmbH&Co. KGaA; Weinheim, Germany: 2009. pp. 39–46.
    1. Doyle J., Quinn R. Adhesives: Types, Mechanics and Applications. Nova Science Publishers; New York, NY, USA: 2011. pp. 47–71.