Cross-linking and gel formation in the thermal degradation of PVC

1976 ◽  
Vol 5 (3) ◽  
pp. 309-315 ◽  
Author(s):  
T. T. Nagy ◽  
B. Turcsányi ◽  
T. Kelen ◽  
F. Tüdős
Keyword(s):  
Thermal Degradation ◽  
Cross Linking ◽  
Gel Formation

scholarly journals Gel Formation in Reversibly Cross-Linking Polymers

2021 ◽  
Author(s):  
Maud Formanek ◽  
Lorenzo Rovigatti ◽  
Emanuela Zaccarelli ◽  
Francesco Sciortino ◽  
Angel J. Moreno
Keyword(s):  
Cross Linking ◽  
Gel Formation

scholarly journals Effect of neutralization and cross-linking on the thermal degradation of chitosan electrospun membranes

2014 ◽  
Vol 117 (1) ◽  
pp. 123-130 ◽  
Author(s):  
D. M. Correia ◽  
M. A. Gámiz-González ◽  
G. Botelho ◽  
A. Vidaurre ◽  
J. L. Gomez Ribelles ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Cross Linking ◽  
Electrospun Membranes

Degradation of Polymers

1962 ◽  
Vol 35 (5) ◽  
pp. 1157-1221 ◽  
Author(s):  
Leo A. Wall ◽  
Joseph H. Flynn
Keyword(s):  
Ionizing Radiation ◽  
Thermal Degradation ◽  
Natural Rubber ◽  
Ultraviolet Light ◽  
Recent Literature ◽  
Chain Scission ◽  
Experimental Results ◽  
Gel Formation ◽  
Vinyl Polymers ◽  
Kinetic Mechanisms

Abstract Recent literature pertaining to both the theoretical aspects and experimental results of the degradation of polymers by heat and radiation is reviewed and critically evaluated. Theories of random and chain thermal degradation of vinyl polymers and co-polymers are reviewed. The degradation of polymethacrylates, polyacrylates, poly-α-methylstyrene, polyolefins, polystyrene, other vinyl polymers, cellulose, polyesters, polyamides, dienes, natural rubber, and copolymers are discussed in the light of these theories. The thermodynamics and energetics of the degradation of these polymers is also reviewed. Chain scission, crosslinking, and gel formation and the kinetic mechanisms of these processes which take place during degradation of polymers by ionizing radiation and ultraviolet light are included. Degradative, rather than synthetic, effects are emphasized in the discussion.

Preventing thermal degradation of PVC insulation by mixtures of cross‐linking agents and antioxidants

2019 ◽  
Vol 137 (24) ◽  
pp. 48816 ◽  
Author(s):  
Witold Brostow ◽  
Nathalie Hnatchuk ◽  
Taehwan Kim
Keyword(s):  
Thermal Degradation ◽  
Cross Linking

Gel formation and molecular weight distribution in long-chain polymers

1954 ◽  
Vol 222 (1151) ◽  
pp. 542-557 ◽  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Average Molecular Weight ◽  
Cross Linking ◽  
Average Weight ◽  
Gel Formation ◽  
Theoretical Derivation ◽  
Experimental Values ◽  
Long Chain

In long-chain polymers an insoluble network or gel may be produced when a number of the separate molecules are linked together. A theoretical derivation is given of the relationship between the amount of gel formed and the degree of cross-linking, in terms of the initial molecular weight distribution. It is shown that whatever the initial molecular weight distribution, incipient gelling occurs when there is on the average one cross-linked monomer per weight average molecule. The shape of the gel-cross-linking curve depends on the ratio of z average, z +1, . . . average molecular weight to the weight average. From experimental values of the curve it becomes possible to determine many of the constants of the molecular weight distribution in the original polymer. Expressions are derived for the number average, weight average and z average of the polymer as a function of cross-linking prior to gel formation, as well as the number and weight averages of the sol fraction after gelation. The average molecular weight between cross-links in the gel is calculated. A number of other functions of the sol and gel fractions are also given.

Sign in / Sign up

Export Citation Format

Share Document