Solid-state polymerization of long-chain vinyl compounds. I. Effect of molecular arrangement on polymerizability of octadecyl methacrylate. [. gamma. -rays]

Journal Article · Wed Aug 01 04:00:00 EDT 1979 · J. Polym. Sci., Polym. Chem. Ed.; (United States)

DOI:https://doi.org/10.1002/pol.1979.170170811· OSTI ID:6012163

Shibasaki, Y; Nakahara, H; Fukuda, K

..gamma..-ray-initiated postpolymerization of octadecyl methacrylate in polymorphic crystals and melt has been investigated to clarify the effect of molecular arrangement of the monomer on polymerizability. From thermal, x-ray, and infrared (IR) analyses this long-chain monomer exhibited three crystalline modifications that we refer to as ..cap alpha..-, sub-..cap alpha.., and ..beta..-forms. The ..beta..-form (mp 28.7 to 29.7/sup 0/C), which is obtainable from solution, is a stable state with triclinic chain packing. The ..cap alpha..-form (mp 19.5 to 20.0/sup 0/C), which is obtained first from the melt but transforms into ..beta..-form on storing, is a metastable state with hexagonal chain packing. The sub-..cap alpha..-form appears transiently in ..cap alpha.. ..-->.. ..beta.. transition. The polymerizability of octadecyl methacrylate in the ..beta..-form is extremely low, whereas the ..cap alpha..-form can polymerize easily and the initial polymerization rate, saturated conversion, and polymer molecular weights increase with temperature. Polymerizability in the molten state at fairly high temperature is rather low, however. Thus maximum polymerizability is obtained just above the melting point of ..cap alpha..-form. It has been found that particular orientation and suitable packing mode with some freedom of rotational motion of the monomer molecules in layered structure accelerate the polymerization reaction. 9 figures.

• Research Organization: Saitama Univ., Urawa, Japan
• OSTI ID: 6012163
• Journal Information: J. Polym. Sci., Polym. Chem. Ed.; (United States), Journal Name: J. Polym. Sci., Polym. Chem. Ed.; (United States) Vol. 17:8; ISSN JPLCA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360402 -- Polymers & Plastics-- Structure & Phase Studies-- (-1987)
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
CARBOXYLIC ACID ESTERS
CARBOXYLIC ACID SALTS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DETECTION
ELECTROMAGNETIC RADIATION
ESTERS
GAMMA RADIATION
INFRARED RADIATION
IONIZING RADIATIONS
METHACRYLATES
METHACRYLIC ACID ESTERS
MOLECULAR STRUCTURE
MONOMERS
ORGANIC COMPOUNDS
PHYSICS
POLYMERIZATION
RADIATION CHEMISTRY
RADIATION DETECTION
RADIATION EFFECTS
RADIATIONS
SOLID STATE PHYSICS
THERMAL ANALYSIS
VINYL MONOMERS
X-RAY DETECTION