Heats of polymerization - a summary of published values and their relation to structure

Abstract

This paper contain s a table showing values of heats of polymerization assembl ed from a survey of t h e li terature. There are 42 substit uted vin yl compounds arranged as follows: vinyl alkyls, vinyl aryls, other vinyls, vi nyl acids and esters, dienes and copoly m ers. Values reported by differen t authors are gi ven for each com pound, wi th correspondin g states of monomers and ploym ers and a notation on t he methods used in obtaining t he values. A second table gives structural formulas of monomers.Some values of heats of polymeri zation to hypothetical polymers having no ste ri c hindrance are calculated from published values of heats of form ation of hydrocarbon s, making ce rtain ass4mptions regardin g branch groups. Th e m ethod of calculation is expla in ed. H eat of polymerization is a rbi t rari ly assigned to four energy effects : (1 ) t he reaction I I I IC= C ---> -C-C-; (2) t he eff ect of side g ro ups on bond energies wh en t he re is no in te r- I I I I .action between the groups; (3) thc eff cct of ste ri c hindrance between ide g roups ; and (4) thc "e nd eff ect" a r isin g from the nearn css of t he double bond to the en d of t he monomer molec ule. Values of hcats of polymerization a re compared , and t he ir relation to s t r ucture is examined, with particular emphasis on t he effect of s teric hindrance. Etyhlene has t he highest and alpha-methylsty rene t he lowes t heat of pol y me ri zation ; isobute nc and the methac rylates also are low. D isubstitution on the same vinyl carbon is a frequent cause of ste ri c interference, with consequent recluctionin heat of polymerization . Large b ra nched substi tuents may causc ste ri c inte rfe rence. The substit u tion of chlorin e on the aromatic ring of styrene has little effect on heat of polym eri zation. Steric interferen ce may prcvent polymerization above the dim e r. The heat of copolymer ization of butadien e an d styrene lics between the values for t he separate monom ers. H eat of copolymeri zation of other monom cr pairs may be higher or lower than the val ue for t he separate compon ents. H eat of polymeriza tion depends somewhat on t he ratio of 1,2-a nd 1,4-addition, and on t he amount of crystallinity of the polymers.

New fluorescein dye derivatives and their use as an efficient photoiniator using blue light LED

“…It is known that the C=C bond requires 60 kJ mol -1 to cleave the ligation, which is considered the standard enthalpy of polymerization (∆ ) [18][19][20][21], and the energy obtained in polymerization peak DSC curves of polymers refers to residual monomer in photopolymerization ( ). Then, the DC (%) can be obtained from DSC curves using Equation 1.…”

Enhancing the Oxidation Stability of Polydivinylbenzene Films via Residual Pendant Vinyl Passivation

“…Such reaction energies are lower than the typical energetic range associated with the polymerization of vinyl aryls in styrene and para-ethylstyrene, ca. 69.7 kJ/mol of monomer, [10] suggesting that the elimination of most of the pendant vinyls does not occur through thermally activated crosslinking. A crosslinking process would be expected to affect the mechanical properties of the bulk polymer.…”

Polymer Nanostructuring by Two-Photon Absorption

“…In order to characterize the photo-reactivity of PFPE resists, the heats of crosslinking reaction were measured by a differential scanning calorimeter coupled with a UV source (UV-DSC), recording sample enthalpy changes when exposed to UV light. The results show that the heats of crosslinking for resists with methacrylate groups are lower than those with acrylates, probably due to the steric hindrance of methyl groups that decrease the reactivity of methacrylates during the polymerization [28,29].…”