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Influence of radical photoinitiators on features of polyacrylate syrups and self-adhesives

Gziut Konrad, Kowalczyk Agnieszka

Polimery

2020

T. 65, nr 4

268--274

Pressure-sensitive adhesives (PSAs) were prepared via UV-irradiaton of an acrylic syrups with reactive diluent (functional diacrylate) and photoinitiator. The acrylic syrups were received via free radical bulk polymerization process (FRBP) and influence of radical photoinitiator (α-hydroxyketones, acylphosphine oxides or mixtures thereof) was investigated. It was revealed that the mixture of bisacylphosphine oxide (Omnirad 819) and α-hydroxyketone (Omnirad 184) was the most effective in FRBP (the highest monomer conversion), but preferable features of acrylic syrups (viscosity and molecular weight of copolymers) and self-adhesive properties of PSAs (especially cohesion) was achieved due to α-hydroxyketones using.

Z syropów akrylanowych oraz wielofunkcyjnego monomeru i fotoinicjatora rodnikowego otrzymano poliakrylanowe kleje samoprzylepne. Syropy akrylanowe uzyskano metodą fotopolimeryzacji w masie monomerów z zastosowaniem różnych fotoinicjatorów rodnikowych (z grupy α-hydroksyketonów, tlenków acylofosfiny i ich mieszanin). Stwierdzono, że najbardziej efektywna w procesie fotopolimeryzacji jest mieszanina fotoinicjatorów: tlenku bisacylofosfiny (Omnirad 819) i α-hydroksyketonu (Omnirad 184) (największa wartość konwersji monomerów), jednak większą lepkością oraz większymi ciężarami cząsteczkowymi cechowały się syropy akrylanowe z udziałem α-hydroksyketonów (Omnirad 127 lub Omnirad 184), a uzyskane z nich kleje wykazywały lepsze cechy samoprzylepne, zwłaszcza kohezję.

Fotopolimeryzacja (met)akrylanów w masie

Gziut Konrad, Kowalczyk Agnieszka

Wiadomości Chemiczne

2019

[Z] 73, 7-8

443--459

Meth(acrylate) polymers are prepared by polymerization according to the radical mechanism. This is possible due to the occurrence of unsaturated double bonds (vinyl groups) in monomers. Meth(acrylate) polymerization reaction is usually carried out in organic solvents using thermal initiators which decompose at elevated temperature to give radicals. An appropriately selected initiator or electromagnetic radiation (e.g. UV light) can be used to initiate the polymerization process. In this case the process is called photopolymerization. Due to the fact that the radical photopolymerization mechanism of met(acrylates) has already been well understood, and the advantages of lightinduced polymerization offer enormous possibilities, this technology still attracts the attention of researchers and industrialists, which results in its continuous development. Meth(acrylates), which are very reactive, are suitable compounds for this technology. Light induced process of transformation these molecules into polymer can be carried out in a very short time. In addition, a wide range of monomers allows to obtain products with various properties. Typically, photopolymerization is associated with the cross-linking of polymers that form part of photocurable compositions, as a result of which, for example, varnish coatings, dental fillings or self-adhesive materials are produced. In this article, contemporary literature on the photopolymerization of (meth)acrylates with reference to the photopolymerization in bulk method is also pointed out. This technique allows to obtain polymer syrups - a polymer solution in unreacted monomers. These viscous liquids are very interesting semi-finished products (free of solvent and almost ready for application) for the preparation of various polymer materials, especially coatings and adhesives.