Free-Radical Frontal Polymerization with a Microencapsulated Initiator:  Characterization of Microcapsules and Their Effect on Pot Life, Front Velocity, and Mechanical Properties

2006 ◽  
Vol 39 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Brian McFarland ◽  
Sam Popwell ◽  
John A. Pojman
e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Stefano Fiori ◽  
Giulio Malucelli ◽  
Alberto Mariani ◽  
Laura Ricco ◽  
Elena Casazza

AbstractThe frontal polymerization technique has been successfully applied, for the first time, to obtain an unsaturated polyester/styrene resin. The effect of the ratio of the two aforementioned components, as well as of the type and amount of free-radical initiator on both front velocity and maximum temperature reached by the front, has been thoroughly studied. The resulting products have been characterized in terms of their thermal and dynamic-mechanical behaviour. A comparison of such products with the corresponding materials obtained by the classical batch polymerization technique has evidenced that frontal polymerization allows to reach a higher degree of crosslinking with respect to batch copolymerization and hence a better thermal and mechanical behaviour.


e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Stefano Fiori ◽  
Alberto Mariani ◽  
Laura Ricco ◽  
Saverio Russo

AbstractInterpenetrating polymer networks made of dicyclopentadiene and methyl methacrylate or tri(ethylene glycol) dimethacrylate have been successfully prepared by non-interfering frontal polymerization. The role of catalyst and free radical initiator relative amounts, as well as of monomer ratio, has been thoroughly studied. The conditions under which a pure frontal polymerization occurs, and the related values of both front velocity and maximum temperature reached by the reaction, are presented and discussed.


2021 ◽  
Author(s):  
Chen Hu ◽  
Malik Salman Haider ◽  
Lukas Hahn ◽  
Mengshi Yang ◽  
Robert Luxenhofer

This work describes the synthesis and detailed characterization of a ternary hybrid hydrogel comprising a thermogelling hydrogel containing laponite clay nanoparticles, in which an additional polymer network is polymerized by free radical polymerization. The precursor hydrogel can be effectively 3D printed and after curing, interesting mechanical properties are obtained.<br>


2021 ◽  
Author(s):  
Chen Hu ◽  
Malik Salman Haider ◽  
Lukas Hahn ◽  
Mengshi Yang ◽  
Robert Luxenhofer

This work describes the synthesis and detailed characterization of a ternary hybrid hydrogel comprising a thermogelling hydrogel containing laponite clay nanoparticles, in which an additional polymer network is polymerized by free radical polymerization. The precursor hydrogel can be effectively 3D printed and after curing, interesting mechanical properties are obtained.<br>


e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Stefano Fiori ◽  
Alberto Mariani ◽  
Simone Bidali ◽  
Giulio Malucelli

Abstract Various crosslinking agents have been used to frontally cure the unsaturated polyester derived by the reaction of maleic anhydride and 1,2-propanediol. The effect of composition of the curing mixture on the front velocity and its maximum temperature, as well as on the thermal properties of the obtained materials, is described.


Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.


Author(s):  
K.L. More ◽  
R.A. Lowden

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.


Author(s):  
Thais Helena Sydenstricker Flores-Sahagun ◽  
Kelly Priscila Agapito ◽  
ROSA MARIA JIMENEZ AMEZCUA ◽  
Felipe Jedyn

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