PMS  (monomer)     para-Methylstyrene

PMS monomer produced by Deltech Corporation is suggested for evaluation as a replacement for vinyltoluene and styrene monomers. PMS monomer has chemical properties and polymerization behavior similar to both vinyltoluene and styrene monomers.
     PMS Molecule     Molecular Weight:   118.18

Typical Isomer Distribution: 99% Para
   1% Meta

In applications where vinyltoluene monomer is replaced by PMS monomer, property improvements related to the higher para-content and polymerizables are obtained. Direct substitution of PMS monomer for vinyltoluene can be made with minimal reformulation to obtain equal or improved performance when used in specialty coatings, sealants and adhesives.

Use of PMS monomer as a partial or complete replacement for styrene monomer in unsaturated polyester resin applications results in lower resin vapor pressure at any temperature and a higher flashpoint. Lower shrinkage during molding, higher thermal properties and greater tensile strength in glass-filled applications can be expected from polymerized resin products.

PMS monomer can replace styrene monomer in homopolymers, impact polymers, acrylonitrile-butadiene terpolymers, specialty copolymers, elastomers and thermosetting polyesters. Homo and copolymers prepared from PMS monomer have been found to possess lower specific gravity, higher flow properties and improved heat distortion than the corresponding styrene-based analogs. In thermosetting polyester applications, higher heat distortion, faster molding cycles, and better electrical properties have been demonstrated. Also, fire retarding properties can be obtained with lower dosages of flame retardant additives and the molecular structure of PMS polymers can be modified through radiation and chemical crosslinking.

Typical precautions in handling PMS monomer include wearing protective clothing, the use of impermeable gloves and use in a well ventilated area. Do not store in direct sunlight. Maintain storage temperature below 75oF if extended storage is required. PMS monomer contains the polymerization inhibitor tertiary butylcatechol (TBC) to reduce polymer formation during storage. For other product safety and toxicological information, please consult the Material Safety Data Sheets for PMS monomer.

Typical Monomer Values

Chemical Analysis Test Method PMS VT Styrene
Purity, Weight % vinyl GC 99.2 99.2 99.7
Isomer Distribution GC      
    Para %   99.0 33.0 --
    Meta %   1.0 66.7 --
    Ortho %   -- 0.3 --
Polymer, ppm ASTM D-2121-84 Neg. Neg. Neg.
Carbonyls, ppm as - CHO ASTM D-2119-82 10 10 10
Inhibitor, ppm TBC ASTM D-4590 25 50 12
Chlorides, ppm XRF 6 5 10
Sulfur, ppm XRF 25 25 25
Physical Properties        
Refractive Index, n25D   1.5408 1.5395 1.5440
Density, g cm-3@ 25oC (77oF)   0.892 0.893 0.902
Viscosity, cps @ 25o   0.79 0.78 0.72
Surface Tension, dynes-cm-1 @ 25oC   34 31 32
Boiling Point, oC @ 760 mm HG   170 168 145
Freezing Point, oC   -34 -77 -31
Volume Concentration on Polymerization        
% calculated @ 25oC   12 12 14
Vapor Pressure, mm HG at        
     40oC (104oF)   4 4 14
     80oC (176oF)   35 35 90
   120oC (248oF)   170 176 368
   160oC (320oF)   580 616 1114
Heat of Polymerization, Kcal mole-1   15-17 15-17 17
Copolymerization Q & e values        
    Q   1.27 1.06 1.00
    e   -0.98 -0.78 -0.80
Heat of Vaporization, cal/g @ 25oC   98.2 -- 102.4
Specific Heat, cal/goC @25oC   0.413 -- 0.408
Solvent Compatibility: Completely compatible with Acetone, Carbon Tetrachloride, Benzene, N-Heptane and Ethanol.

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Nothing contained herein is to be construed as a recommendation to use any product in conflict with any patent. Deltech Corporation makes no warranties as to the fitness of merchantability of any product referred to, no guarantee of satisfactory results from reliance upon contained information or recommendation, and disclaims all liability for any resulting loss or damage.