scholarly journals Epoxy-Based Structural Self-Adhesive Tapes Modified with Acrylic Syrups Prepared via a Free Radical Photopolymerization Process

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 189
Author(s):  
Konrad Gziut ◽  
Agnieszka Kowalczyk ◽  
Beata Schmidt ◽  
Krzysztof Kowalczyk ◽  
Mateusz Weisbrodt
Keyword(s):  
Shear Strength ◽  
Free Radical ◽  
Dynamic Viscosity ◽  
Glycidyl Methacrylate ◽  
Bulk Polymerization ◽  
Butyl Methacrylate ◽  
Crosslinking Degree ◽  
Mixing Speed ◽  
Molecular Weights ◽  
Free Radical Photopolymerization

New modifiers (i.e., acrylic syrups; ASs) of epoxy-resin-based thermally curable structural self-adhesive tapes (SATs) were prepared via a free radical bulk polymerization (FRBP) of n-butyl acrylate, butyl methacrylate, glycidyl methacrylate, and hydroxybutyl acrylate. In the process, two kinds of UV-photoinitiators (i.e., monoacylphosphine oxide/Omnirad TPO and bisacylphosphine oxide/Omnirad 819) and various mixing speed of the monomers mixture (200–1000 rpm) were applied. The TPO-based syrups exhibited a lower copolymers content (10–24 wt%), dynamic viscosity (<0.1 Pa·s), molecular weights (Mn and Mw, and polydispersity (1.9–2.5) than these with Omnirad 819. Additionally, the higher mixing speed significantly reduced monomers conversion and viscosity of ASs as well as molecular weights of the acrylate copolymers. These parameters influenced the properties of thermally uncured (e.g., adhesion) and thermally cured SATs (shear strength of aluminum/SAT/aluminum overlap joints). Better self-adhesive features were observed for SATs-TPO (based on ASs with lower monomers conversion, Mn and Mw); however, a slightly higher shear strength was noted for the thermally cured SAT-819 (ASs with higher monomers conversion, Mn and Mw). An impact of polydispersity of the acrylate copolymers as well as crosslinking degree of thermally cured SATs on the mechanical strength was also revealed.

Diazonium salt-based photoiniferter as a new efficient pathway to clay–polymer nanocomposites

RSC Advances ◽  
2016 ◽  
Vol 6 (91) ◽  
pp. 88126-88134 ◽  
Author(s):  
Hanène Salmi-Mani ◽  
Zouhair Ait-Touchente ◽  
Aazdine Lamouri ◽  
Benjamin Carbonnier ◽  
Jean-François Caron ◽  
...  
Keyword(s):  
Free Radical ◽  
Polymer Nanocomposites ◽  
Glycidyl Methacrylate ◽  
Diazonium Salt ◽  
Diazonium Salts ◽  
Mass Loading ◽  
Organic Mass ◽  
Free Radical Photopolymerization

Diazonium salts were used to prepare clay–polymer nanocomposites by living free radical photopolymerization of glycidyl methacrylate. The resulting intercalated nanocomposites have an organic mass loading of ∼41 wt% and a polymer-rich surface.

scholarly journals Free-Radical Bulk-Photopolymerization Process as a Method of Obtaining Thermally Curable Structural Self-Adhesive Tapes and Effect of Used Type I Photoinitiators

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2191 ◽  
Author(s):  
Konrad Gziut ◽  
Agnieszka Kowalczyk ◽  
Beata Schmidt
Keyword(s):  
Free Radical ◽  
Glycidyl Methacrylate ◽  
Butyl Methacrylate ◽  
Cross Linking ◽  
Type I ◽  
Fabrication Method ◽  
Thermal Curing ◽  
Scanning Calorimetry ◽  
Nmr Studies ◽  
Physico Chemical

A new fabrication method for thin (120 µm) thermally curable structural self-adhesive tapes (SATs) was demonstrated by utilizing a series of acrylic syrups (ASs) modified using Bisphenol A-based liquid epoxy resin. The acrylic syrups containing poly(butyl acrylate-co-butyl methacrylate-co-glycidyl methacrylate-co-2-hydroxyetyl acrylate-co-4-acryloyloxy benzophenone) were synthesized via free-radical bulk-photopolymerization (FRBP) process. Influence of different type I radical photoinitiators (PIs), i.e., α-hydroxyalkylphenones (HPs), acylphosphine oxides (APOs) and its mixtures (HPs/APOs and APO/APO) on selected physico-chemical features of obtained ASs was studied. It turned out that APO-type PIs are more effective in the FRBP process (NMR studies). Self-adhesive tests of SATs revealed that the monomers’ conversion in ASs have a significant influence on adhesion and tack. Moreover, the polymer structures formed at the UV cross-linking stage of SATs significantly affect the cross-linking degree of SATs during thermal curing (differential scanning calorimetry method). The highest values of overlap shear strength were achieved by SATs based on ASs with monomers’ conversion on the level 50–60%.

scholarly journals Cubane Cu4I4(phosphine)4 Complexes as New Co-initiator for Free Radical Photopolymerization: Towards Aromatic Amine-Free Systems

2021 ◽  
Author(s):  
Jacques Lalevée ◽  
Fatima Hammoud ◽  
Mahmoud Rahal ◽  
Julien Egly ◽  
Fabrice Morlet-Savary ◽  
...  
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Aromatic Amine ◽  
Free Radical Polymerization ◽  
Copper Iodide ◽  
Free Radical Photopolymerization ◽  
Acrylate Monomers ◽  
First Time

The investigation of copper-iodide cubane derivatives as new co-initiators for the free radical polymerization (FRP) of acrylate monomers under mild irradiation conditions is described for the first time here. These...

Star-shaped Polymers through Simple Wavelength-Selective Free-Radical Photopolymerization

2017 ◽  
Vol 56 (45) ◽  
pp. 14306-14309 ◽  
Author(s):  
Anna Eibel ◽  
David E. Fast ◽  
Jürgen Sattelkow ◽  
Michal Zalibera ◽  
Jieping Wang ◽  
...  
Keyword(s):  
Free Radical ◽  
Free Radical Photopolymerization

scholarly journals Radical scavenging activity of crude polysaccharides from Camellia sinensis

2011 ◽  
Vol 63 (3) ◽  
pp. 717-721
Author(s):  
Fan Yang ◽  
Zhiwei Yang ◽  
Jianbo Xiao
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
Camellia Sinensis ◽  
Superoxide Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Dependent Manner ◽  
Scavenging Activity ◽  
Concentration Dependent Manner ◽  
Molecular Weights

A preparation of crude polysaccharides (TPS) was isolated from Camellia sinensis by precipitation and ultrafiltration. TPS1, TPS2, and TPS3 had molecular weights of 240, 21.4, and 2.46 kDa, respectively. The radical scavenging activities of TPS were evaluated by DPPH free radical, hydroxyl radical and superoxide radical scavenging. These results revealed that TPS exhibited strong radical scavenging activity in a concentration-dependent manner. TPS3 with lowest molecular weight showed a higher radical scavenging activity.

Photopolymerization of methyl methacrylate: effects of photochemical and photonic parameters on the chain length

2014 ◽  
Vol 5 (21) ◽  
pp. 6236-6243 ◽  
Author(s):  
V. Charlot ◽  
A. Ibrahim ◽  
X. Allonas ◽  
C. Croutxé-Barghorn ◽  
C. Delaite
Keyword(s):  
Free Radical ◽  
Methyl Methacrylate ◽  
Chain Length ◽  
Free Radical Photopolymerization

The effects of photochemical and photonic parameters are investigated on the chain length of poly(methylmethacrylate) (PMMA) as formed by the free radical photopolymerization process.

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