Synthesis and Characterization of Functionally Gradient Materials Obtained by Frontal Polymerization

Abstract

Functionally gradient materials (FGMs) with gradual and continuous changes of their properties in one or more dimensions are useful in a wide range of applications. However, obtaining such materials with accurate control of the gradient, especially when the gradient is nonlinear, is not easy. In this work, frontal polymerization (FP) was exploited to synthesize polymeric FGMs. We demonstrated that the use of ascending FP with continuous feeding of monomers with computer-controlled peristaltic pumps provided an excellent method for the preparation of functionally gradient materials with programmed gradients. To test the effectiveness of the method, copolymers made from triethylene glycol dimethacrylate/hexyl methacrylate with linear and hyperbolic gradient in composition were synthesized. Differential scanning calorimetry (DSC), Shore A hardness measurements, compression tests, and swelling studies were performed along the length of the materials to assess the relationship between the gradients and the material properties. Glass transition temperatures, determined by DSC, showed a linear dependence on the composition and were in agreement with theoretical values. The other properties showed different and specific behaviors as a function of the compositional gradient.

Effect of limonene on the frontal ring opening metathesis polymerization of dicyclopentadiene

“…Frontal polymerization (FP) is a synthetic technique that allows the conversion of monomer into polymer by formation and consequent propagation of a hot polymerization front, able to self‐sustain and propagate throughout the monomeric mixture. This technique allows obtaining polymer materials by a simple reaction route, short time, and low energy consumption …”

Semi‐interpenetrating polymer networks based on crosslinked poly(N‐isopropyl acrylamide) and methylcellulose prepared by frontal polymerization

“…If compared with the traditional polymerization methods, FP is generally characterized by several advantages, including simple protocols, short reaction times, and high yields. FP was extensively studied by Pojman and coworkers, Tonoyan and coworkers, Mariani and coworkers, Chen and coworkers, and others …”

“…If compared with the traditional polymerization methods, FP is generally characterized by several advantages, including simple protocols, short reaction times, and high yields. FP was extensively studied by Pojman and coworkers, [15][16][17] Tonoyan and coworkers, [18][19][20][21] Mariani and coworkers, [22][23][24][25][26][27] Chen and coworkers, 10,28-31 and others. [32][33][34][35][36][37][38] Very recently, Mariani and coworkers succeeded in obtaining semi-interpenetrating polymer networks (SIPNs) of methyl cellulose and crosslinked polyacrylamide, exploiting the frontal polymerization technique.…”

Synthesis of gradient copolysiloxanes by simultaneous copolymerization of cyclotrisiloxanes and mechanism for kinetics inverse between anionic and cationic ring‐opening polymerization

“…For instance, incorporation of fluorinated polysiloxane blocks into conventional vinyl polysiloxanes results in the formation of the block copolymers with thermal resistance, superior damping properties, and fuel resistance. However, in recent years, gradient copolymers of different siloxane units have gradually produced extensive concern because of their potential unique properties which are significantly different compared with the properties of block and random copolymers . Gradient copolymers are a novel class of polymers that exhibit a gradual change in composition along the chain .…”

“…However, in recent years, gradient copolymers of different siloxane units have gradually produced extensive concern because of their potential unique properties which are significantly different compared with the properties of block and random copoly-mers. 6,[17][18][19] Gradient copolymers are a novel class of polymers that exhibit a gradual change in composition along the chain. 17,[20][21][22][23][24][25][26][27][28] They can potentially be used as polymer blend compatibilizers, surfactants, and environment-sensitive materials.…”