It should be remembered that a number of factors influence the kinetics of the polymerization reaction
. The most important are the concentration of initiators (the higher the initiator concentration, the faster the reaction occurs), concentration of monomer, pressure, and temperature.
However, dual cure cements contain tertiary amines for initiation of polymerization which are implicated in compromising their color stability.7 By contrast, photo-polymerized resin cements use Norrish Type-II photo initiator (camphorquinone) to induce free radical formation resulting in polymerization reaction
.6 In addition, photo-polymerized cements show better color stability (as no tertiary amines are used as chemical activator) and have ambient working time.8 However degree of polymerization for photopolymerized cements depends on light penetration and exposure, which is influenced by the thickness and translucency of adhesively bonded restorations.9
Broadbelt, Ab Initio Study of Acrylate Polymerization Reactions
: Methyl Methacrylate and Methyl Acrylate Propagation, J.
The reaction can take place on different interfaces such as gas/solid or liquid/solid interface, and the solid substrate serves to support the polymerization reaction
without strict limitation of materials.
It entails a blend containing a UV-absorbing polymer comprising the polymerization reaction
product of a first ethylenically unsaturated monomer comprising a first pendant group that comprises a UV-absorbing moiety, and a second pendant group selected from the group consisting of H, or C1.
The temperature increase was due to the exothermic heat of the polymerization reaction
. Since it was condensation-type polymerization, polymerization was accelerated by the removal of water.
Though kinetically unfavorable, if it were to occur, this mechanism would slow down the overall polymerization reaction
, even with low quantum yields, by removing both ITX and MA from the photoinitiator system.
The polymerization reaction
starts as the mixture enters the mold.
Powders can form inside the pump, where the conditions of high temperature and pressure promote a polymerization reaction
. Vacuum pumps can be destroyed as a result, with pump life being as short as eight weeks.
Although there is general agreement that one of the first steps in the polymerization reaction
of G-actin into F-actin filaments involves dimerization of a significant fraction of the monomer pool, evidence has been presented that this dimer - called the "lower dimer" (LD) - is in a G-like conformation and is, by itself, unable to polymerize into F-actin filaments (Millonig et al., 1988).
Anaeorobic sealants are composed of methacrylates, and involve two chemical systems: 1) a monomeric system that polymerizes, in the absence of oxygen, into a rubberlike compound, and 2) an initiator system that starts the polymerization reaction
. The presence of metal ions is essential for this reaction to proceed.
The actual polymerization reaction
starts with the addition of a catalyst or initiator.
The process uses thermoplastics such as polycarbonate and polyetherimides, which engineers can reshape with heat treatments even after the initial polymerization reaction
. Most existing composites involve thermosetting polymer resins that take on an unalterable shape once polymerized.
It becomes evident that polymer microspheres or porous polymer composites containing ordered carbon structure formed by GO or CNTs can be conveniently acquired by initiating the polymerization reaction
. The influences of covalent functionalization and noncovalent modification on the GO or functionalized CNTs stabilized Pickering emulsion have been studied for several o/w and w/o systems with an emphasis on tuning the amphiphilicity of stabilizer, which is one of the paramount factors governing the morphology and performance of the resulting emulsion and final polymer nanocomposites [27-29].
Emulsion-based peroxides also contain an anti-freeze agent, preventing the ice crystal formation that sometimes occurs in solvent-based solutions, which can affect the feeding of initiator to the polymerization reaction
. This also improves the product quality of the finished PVC product.