Related Experiment Video
Updated: Sep 24, 2025
09:06
Evaluation of the Curing of Adhesive Systems by Rheological and Thermal Testing
Published on: July 3, 2020
7.4K
Microstructural study of epoxy-based thermosets prepared by "classical" and cationic frontal polymerization.
Helena Švajdlenková1,2, Angela Kleinová1, Ondrej Šauša3
1Department of Synthesis and Characterization of Polymers, Polymer Institute of SAS Dúbravská cesta 9 Bratislava 845 41 Slovakia helena.svajdlenkova@savba.sk.
RSC Advances
|May 6, 2022
Summary
This study reveals that photo- and thermally-induced cationic frontal polymerization of bisphenol-A diglycidyl ether (BADGE) epoxides create superior microstructures. These advanced epoxides exhibit enhanced material properties compared to conventionally cured samples.
Area of Science:
- Polymer Chemistry
- Materials Science
- Physical Chemistry
Background:
- Understanding epoxide microstructure is key to optimizing material properties.
- Cationic frontal polymerization (CFP) offers novel routes for epoxide synthesis.
- Investigating structure-property relationships in CFP-synthesized epoxides is crucial.
Purpose of the Study:
- To compare microstructural characteristics of bisphenol-A diglycidyl ether (BADGE) epoxides prepared via conventional, photo-induced CFP, and thermally-induced CFP.
- To correlate microstructural features (e.g., free volume, H-bonding) with material properties.
- To analyze the dynamics of frontal polymerization waves.
Main Methods:
- Positron Annihilation Lifetime Spectroscopy (PALS) to probe free volume and microstructure.
- Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR/FTIR) to assess hydrogen bonding.
- Differential Scanning Calorimetry (DSC) and thermal conductivity measurements to analyze thermal profiles.
- Analysis of radial and angular profiles of free volume fraction.
Main Results:
- Photo-triggered RICFP propagation is twice as fast as thermally-induced RICFP.
- Both RICFP methods yield lower ortho-positronium lifetimes (τ₀), narrower lifetime distributions, and reduced void fractions compared to conventional curing.
- Maximal reaction temperatures and heat conductivity were comparable between photo- and thermally-induced RICFP.
- Experimental data confirmed the rotational movement of frontal polymerization waves and their impact on microstructural inhomogeneities.
Conclusions:
- RICFP, particularly photo-triggered, offers a route to epoxides with improved microstructural characteristics and potentially enhanced material properties.
- Reduced free volume and altered H-bond networks are key microstructural differences contributing to improved properties.
- Frontal polymerization dynamics significantly influence microstructural development and final material performance.
More Related Videos
11:17Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction
Published on: January 19, 2016
22.1K
06:55Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
Published on: September 26, 2016
8.0K
Related Concept Videos
00:57Cationic Chain-Growth Polymerization: Mechanism
2.4K
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the...
2.4K
01:26Polymer Classification: Stereospecificity
2.7K
Polymerization generates chiral centers along the entire backbone of a polymer chain. Accordingly, the stereochemistry of the substituent group has a significant effect on polymer properties. Polymers formed from monosubstituted alkene monomers feature chiral carbons at every alternate position in the polymer backbone. Relative to the predominant orientation of substituents at the adjacent chiral carbons, the polymer can exist in three different configurations: isotactic, syndiotactic, and...
2.7K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.1K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.1K
02:24Acid-Catalyzed Ring-Opening of Epoxides
7.7K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
7.7K
01:13Olefin Metathesis Polymerization: Overview
2.3K
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
2.3K
03:00Preparation of Epoxides
8.2K
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...
8.2K