fi-Picolinium-p-chlorophenacylide (fi-PCPY) acts as a retarder for polymerization of N-vinyl pyrrolidone. The polymerization runs were carried out at 60 ~ using benzene as an inert solvent. The kinetic equation for the present system may be written 066 10 .' . as Rpa[fl-PCPY] -1'0 [AIBN] " [N-VP] " . The value of overall energy of actlvatlon for pol,Ym11 erization in presence and absence of fi-PCPY was computed as 44.0 and 42.3 kJ tool-, respectively. The inverse relationship of Rp and My with fl-PCPY suggests thatfl-PCPY acts as a polymerization retarder. The retarding effect is also evidenced by higher initiator exponent value and higher value of energy of activation in presence of ylide. A mechanism is also proposed in which polymer propagating chain combines with one ylide component to give resonance stabilized radical.
Synthesis of a series of novel terpolymers, consisting of two electron‐donating monomers, viz. N‐vinyl pyrrolidone (N‐VP) (heterocyclic polar monomer) and styrene (Sty) (non‐polar monomer), with one electron‐accepting polar monomer, i.e. acrylonitrile (AN), using α,α'‐azobisisobutyronitrile as radical initiator and benzene as diluent at 60°C, has been extensively surveyed. Besides the synthesis, an attempt has been made to study the kinetics and various properties of the terpolymers, such as softening temperature and chemical resistance. The system follows non‐ideal kinetics and the kinetic equation for the present system can be written as
This non‐ideality can be explained on the basis of significant initiator‐dependent termination through primary radicals and degradative chain transfer to acrylonitrile monomer. The overall energy of activation is 72.4 kJ mol−1 and kp2/kt is 0.26 × 10−3 litre mol−1 s−1.
The effects of various additives such as imidazolium‐p‐chlorophenacylide (ICPY) and ZnCl2 were also studied. ICPY functions as a chain transfer agent (Ctr = 0.43 × 10−4), whereas ZnCl2 accelerates the rate of reaction. IR spectroscopy was used to confirm the structure of the terpolymers.
SUMMARY:The polymerization of methyl methacrylate (MMA) initiated by a-picolinium-pchlorophenacylide in CCl, at 30, 35, and 40°C for four h was investigated dilatometrically. The orders of reaction with respect to the concentrations of ylide and MMA are 0. bzw. 0,37 * lo-'. Die Ergebnisse wurden als radikalische Polymerisation mit einer initiatorabhangigen ubertragung und einem bimolekularen Abbruch erkl5lrt.
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