autoacceleration


Also found in: Wikipedia.

autoacceleration

[¦ȯd·ō·ik‚sel·ə′rā·shən]
(organic chemistry)
The increase in polymerization rate and molecular weight of certain vinyl monomers during bulk polymerization.
References in periodicals archive ?
The main motivation to search for other models for the simulation of the photopolymerization process was to see the effects of autoacceleration, autodeceleration, volume shrinkage, and reaction diffusion terms on the system besides the basic photopolymerization reaction mechanisms of initiation, propagation, and termination.
However, the various phenomena of autoacceleration, unequal reactivity of different functional groups, multiple termination processes, volume shrinkage, and the heterogeneities of the networks formed make the understanding of the mechanisms difficult.
ABSENCE OF AUTOACCELERATION IN AROMATIC SULFONYL AZIDES AS FREE-
Unlike as reported in this paper for nylon fibers, the property gradients in polypropylene fibers were attributed to autoacceleration by surface oxidation during processing or screening by UV absorbing additives.
6 and 7, some typical features of the curing process are represented, such as autoacceleration and autodeceleration, which are in agreement with theoretical predictions.
ABSENCE OF AUTOACCELERATION IN AROMATIC SULFONYL AZIDES AS FREE-RADICAL INITIATORS FOR PHOTOPOLYMERIZATION
The data illustrates autoacceleration immediately after irradiation commences so that the reaction rate reaches a maximum value at a double bond conversion of about 10%.
With the process of reaction, three-dimensional gel structure is formed, which restricts the diffusion and mobility of macroradicals and pendant double bonds, slowing down the radical termination rate, which leads to autoacceleration.
Indeed, if the proposed mechanism is valid, one would expect autoacceleration and chain scissions after a certain exposure time (longer than 1200 h) at 20 [degrees]C, because hydroperoxides also accumulate at this temperature.
A reduction in the termination rate accumulated radical population and thus resulted in an autoacceleration in the polymerization rate.
But in the experiment, the gel effect often takes place at intermediate or high degrees of polymerization, and then results in the autoacceleration of the rate of the polymerization [38, 39].
A minor autoacceleration in the polymerization rate started to appear in 243 min.