SynopsisThe properties of poly-N-vinylcaprolactam organic and aqueous solutions were studied.Aqueous solutions present a very accentuated diminishing of [ q ] from 10 to 30°C. Above 30°C. the polymer precipitates from ita aqueous solutions. The precipitation temperature does not depend on the concentration but on the molecular weight of the polymer. Some acid and basic agents have a marked inhence on [q] and the precipitation temperature of the aqueous solutions.Toluene solutions present an increasing [?] from 10 to 40°C.There are no studies about the behavior of poly-N-vinylcaprolactam solutions. It is only known that some poly-N-vinyllactams precipitate with heat from their aqueous solutions.The temperature at which the precipitation phenomenon appears is dependent on the number of C atoms of the lactamic ring: for po1y-Nvinylcaprolactam this temperature is about 35°C. and for poly-N-vinylpiperidone it is 64-65OC.lIn the case of poly-N-vinylpyrrolidone such a precipitation does not take place in the usual temperttture range (O--lOO°C.). It was admitted that this abnormal phenomenon is due to the colloidal nature of aqueous solutions of poly-N-vinyllactams,2 and it was supposed that the increasing temperature diminishes the polymer ~olvation.~ The object of the present work was the study of the behavior of po1y-Nvinylcaprolactam solutions from the viewpoint of their viscosity and of the factors that influence the temperature at which the polymer precipitates from its aqueous solutions.
SynopsisBulk radical polymerization of N-vinylcaprolactam was studied at temperatures between 60 and 120'C. with different initiators. Satisfactory results were obtained with azobisisobutyronitrile, terl-butyl perbenzoate, and tert-butyl peroxide as initiators. The polymerization reaction of N-vinylcaprolectam with these initiators is first order witch respect to the monomer and 0.5 order with respect to the initiator. A linearity of the kinetic curves up to high conversions was observed. The cause of this behavior is a feeble gel effect, which also induces an increase of the molecular weight during polymerization.N-vinylcaprolactam polymerization was studied with HzOz and benzoyl peroxide as initiators at temperatures over 100°C. ; low molecular weight polymers were Satisfactory results were obtained with azobisisobutyronitrile as initiator13 but there are no published data on the kinetics of this reaction.
ExperimentalThe monomer was obtained by vinylation of caprolactam with acetylene in the presence of caprolactyl N-Vinylcaprolactam was isolated from the reaction mass by distillation at reduced pressure (8-10 mm.) under argon; it then was purified by being distilled twice under argon at 8-10 mm. through a rectification column (4 = 30 mm., h = 700 mm.) filled with glass rings (4 = 4 mm., h = 5 mm.), the reflux ratio being SOTo; the fraction was collected directly in ampules at temperatures between 11O.S and 111.2"C. The ampules containing pure monomer were closed under argon. I n such conditions pure N-vinylcaprolactam (ng = 1.5057, freezing point 345°C.) may be conserved a long time at room temperature in the dark.The pure moiiomer was handled only uiider dry, inert atmosphere. The precautionary measures of purifying, conserving, and handling of the N-vinylcaprolactam were necessary because of the sensitivity of this monomer to the action of oxygen, which oxidizes rapidly to a brown-yellow compound. The presence of such compounds diminishes considerably the activity of N-vinylcaprolactam in the polymerization reaction, and the results of kinetic measurements became unreproducible.
1843
synopsisThe bulk polymerization of 2-allylphenylscrylic ester and of 2-allylphenylmethacrylic ester at 60-80°C. was studied. It was observed that under these conditions azobisisobutyronitrile, lauroyl peroxide, and benzoyl peroxide have satisfactory activity as initiators. The influence of atmospheric oxygen on AOAF and MOAF polymerization was proved. The peculiarities of AOAF and MOAF polymerization (low molecular weight of the soluble polymers which are formed, the absence of gel effect, relatively low critical conversions) may be explained on the basis of chain transfer reactions by the allylic groups.It is known that the radical bulk polymerization of tetrafunctional monomers occurs with formation of crosslinked, insoluble, and infusible polymers. For this reason this reaction is usually named "crosslinking polymerization " or ilthredimensional polymerization." There are a lot of works dealing with this type of reaction, some of which have a special importance for the explaining of gel-formation, geleff ect, cyclization, and other phenomena which are taking place during the three-dimensional polymeri~ation.l-~ The research in this field was directed almost exclusively towards the study of polymerization of symmetric tetrafunctional monomers.Acrylic and methacrylic esters of 2-allylphenol (AOAF and MOAF) are asymmetric tetrafunctional monomers. The molecules contain two unsaturated, structurally different groups, the allylic and the acrylic (methacrylic) ones, which have a different reactivity in the polymerization reaction.The synthesis and polymerization of AOAF were not described till now, lo and very little work has been found on the synthesis and polymerization of MOAF and the properties of respective polymers.11*12The present work refers to the study of AOAF' and MOAF radical bulk polymerization.
1631
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