Study of the free-radical polymerization of styrene by differential scanning calorimetry

1973 ◽  
Vol 45 (4) ◽  
pp. 804-806 ◽  
Author(s):  
John R. Ebdon ◽  
Barry J. Hunt
Keyword(s):  
Differential Scanning Calorimetry ◽  
Free Radical ◽  
Radical Polymerization ◽  
Free Radical Polymerization ◽  
Scanning Calorimetry

scholarly journals Photocurable Epoxy Acrylate Coatings Preparation by Dual Cationic and Radical Photocrosslinking

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4150
Author(s):  
Paulina Bednarczyk ◽  
Karolina Mozelewska ◽  
Małgorzata Nowak ◽  
Zbigniew Czech
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Free Radical Polymerization ◽  
Hybrid Coatings ◽  
Epoxy Acrylate ◽  
Structural Factors ◽  
Scanning Calorimetry ◽  
Yellowness Index ◽  
Hybrid Resin ◽  
Industrial Grade

In this work, epoxy acrylate resin (EA) based on the industrial-grade bisphenol A-based epoxy resin (Ep6) and acrylic acid (AA) has been synthesized in order to develop hybrid resin comprising both epoxide group and reactive, terminal unsaturation. Obtained epoxy acrylate prepolymer was employed to formulate photocurable coating compositions containing, besides the EA binder, also cationic or radical photoinitiators. Hence, when cationic photoinitiators were applied, polyether-type polymer chains with pending acrylate groups were formed. In the case of free radical polymerization, epoxy acrylates certainly formed a polyacrylate backbone with pending epoxy groups. Owing to the presence of both epoxy and double carbon–carbon pendant groups, the reaction product exhibits photocrosslinking via two distinct mechanisms: (i) cationic ring-opening polymerization and (ii) free radical polymerization. Therefore, photopolymerization behavior of synthetized hybrid resin with various photoinitiators was determined via photo-differential scanning calorimetry (photo-DSC) and real-time infrared spectroscopy (RT-IR) methods, and properties of cured coatings were investigated. The performance of the following type of photoinitiators was tested in the cationic photopolymerization: diaryliodonium cations or triarylsulfonium cations, and the following type of photoinitiators were used to induce free radical photopolymerization: α-hydroxyketones, acylphosphine oxides, and their mixtures. Lastly, the basic physicomechanical properties of cured coatings, such as tack-free time, hardness, adhesion, gloss, and yellowness index, were evaluated. Some structural factors and parameters of cationic and radical photoinitiators and photopolymerization mechanisms affecting the epoxy acrylate hybrid coatings performance are discussed.

scholarly journals Effect of temperature on initial stage of methyl methacrylate free radical bulk polymerization

2010 ◽  
Vol 64 (6) ◽  
pp. 503-510
Author(s):  
Vladislav Jaso ◽  
Dragoslav Stoiljkovic ◽  
Radmila Radicevic
Keyword(s):  
Experimental Data ◽  
Free Radical ◽  
Methyl Methacrylate ◽  
Radical Polymerization ◽  
Free Radical Polymerization ◽  
Bulk Polymerization ◽  
Effect Of Temperature ◽  
Scanning Calorimetry ◽  
Initial Stage ◽  
Classic Theory

Classic theory of free radical polymerization is based on two assumptions. The first is that the concentration of initiator is slightly changed and could be taken as a constant value. The second assumption is that the rate of initiation is equal to the rate of termination. Equation for the polymerization rate based on these assumptions can not successfully describe the initial stage of free radical polymerization. In order to solve this problem, three mathematical models were developed and used to verify of the mentioned assumptions. The models were fitted to experimental data and qualities of their fits were compared. Experimental data of isothermal bulk polymerization of methyl methacrylate were obtained by differential scanning calorimetry at 60, 70, 80 and 90?C with initiator concentration (AIBN) of 0.5 wt%. The best fit was shown by the model that assumes constant concentration of initiator during initial stage but takes into account that the rate of initiation is not equal to the rate of termination at the beginning.

Non-isothermal Kinetics of Free Radical Polymerization of 2-Phenylethyl (Meth)acrylate

2018 ◽  
Vol 8 (3) ◽  
pp. 585-594
Author(s):  
Khdbudin Mulani ◽  
Ravindra Ghorpade ◽  
Surendra Ponrathnam ◽  
Nayaku Chavan ◽  
Kamini Donde
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Free Radical Polymerization ◽  
Isothermal Kinetics ◽  
Kinetics Of

Oxygen-Initiated Free-Radical Polymerization of Alkyl Acrylates at High Temperatures

2021 ◽  
Author(s):  
Shi Liu ◽  
Lauren Chua ◽  
Ahmad Arabi Shamsabadi ◽  
Patrick Corcoran ◽  
Abhirup Patra ◽  
...  
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
High Temperatures ◽  
Free Radical Polymerization ◽  
Alkyl Acrylates
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