Self Organization in Synthetic Polymeric Systems

POJMAN, JOHN A.

doi:10.1111/j.1749-6632.1999.tb10420.x

Cited by 10 publications

(12 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The authors employed multivariant statistical analysis to identify correlations between formulation conditions and foam topology within the ≈ 70 formulations tested. Similar polymer self-organization behavior in FP was also observed in early work by Pojman and coworkers 330,331 5.4 Organic and Organic-Inorganic Composite Materials…”

Section: Instability Driven Spontaneous Patterningsupporting

confidence: 78%

Frontal Polymerizations: From Chemical Perspectives to Macroscopic Properties and Applications

Suslick

Hemmer

Groce

et al. 2022

Preprint

View full text Add to dashboard Cite

The synthesis and processing of thermoplastics and thermoset polymeric materials rely on energy-inefficient and environmentally burdensome manufacturing methods. Frontal polymerization has emerged as an attractive, scalable alternative due to its exploitation of the heat of polymerization, which generally is wasted as unutilized heat-loss. The only external energy needed for frontal polymerization is an initial thermal (or photo) stimulus that locally ignites the reaction. The subsequent reaction exothermicity provides local heating; the transport of this thermal energy to neighboring monomers in either a liquid or gel-like state results in a self-perpetuating reaction zone that provides fully-cured polymeric thermosets and thermoplastics. Propagation of this polymerization front continues through the unreacted monomer media until either all reactants are consumed or sufficient heat-loss stalls further reaction. Several different polymerization mechanisms support frontal processes, including free-radical, cat- or anionic, amine-cure epoxides, and ring-opening metathesis polymerization. The choice of monomer, initiator/catalyst, and additives dictates how fast the polymer front traverses the reactant medium, as well as the maximum temperature achievable. Frontal polymerization enables the preparation of moldable thermoplastics derived from linear polymers. When crosslinking is involved, polymeric networks (e.g., rigid thermosets) are obtainable through a related process best described as a frontal curing reaction. Numerous applications of frontally-generated polymers and thermosets exist, ranging from the reinforcement of porous substrates to the design of patterned composite materials. In this review, we examine in detail the physical and chemical phenomena that govern frontal polymerization, as well as outline the existing applications.

show abstract

Section: Instability Driven Spontaneous Patterningsupporting

confidence: 78%

Frontal Polymerizations: From Chemical Perspectives to Macroscopic Properties and Applications

Suslick

Hemmer

Groce

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…[ 15,16 ] Moreover, formation of structural solids with nonrandom patterns were observed by Pojman during the FP of acrylates. [ 17 ] However, the directional characteristics of FP have not yet been explored to control the morphology of porous materials.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Foams via Frontal Polymerization

et al. 2022

View full text Add to dashboard Cite

The properties of foams, an important class of cellular solids, are most sensitive to the volume fraction and openness of its elementary compartments; size, shape, orientation, and the interconnectedness of the cells are other important design attributes. Control of these morphological traits would allow the tailored fabrication of useful materials including highly porous solids, anisotropic heat conductors, tough composites, among others. While approaches like ice templating has produced foams with elongated cells, there is a need for rapid, versatile, and energy efficient methods that also control the local order and macroscopic alignment of cellular elements. Here we describe a fast and convenient method to obtain anisotropic structural foams using frontal polymerization. We fabricated foams by curing mixtures of dicyclopentadiene and a physical blowing agent via frontal ring opening metathesis polymerization (FROMP). The materials were characterized using micro-computed tomography and an image analysis protocol to quantify morphological characteristics including volume fraction and anisotropy. The cellular structure, porosity, and hardness of the foams changed with blowing agent, concentration, and resin viscosity. Moreover, we used a full factorial combination of variables to correlate each parameter with the structure of the obtained foams. We found a strong correlation between the resin viscosity and the foam's cellular structure. Furthermore, a specific combination of input parameters controlled the transitions from (i) isotropic to anisotropic cellular structures, (ii) porous to non-porous, and (iii) soft to hard foams. Our results demonstrate the controlled production of foams with specific morphologies using the simple and efficient method of frontal polymerization. This work shows promise for creating foams with aligned cellular structures that allow anisotropic mass and energy transport properties in high performance structural solids.

show abstract

“…According to J. A. Pojman 50 , this pattern was indicative to a macroscale phase separation of two reactants in a mixture by their individual crosslinking during FP. To assess the effects of these selective crosslinking to the construct of the polymerized millichannel microstructure, the field-emission scanning electron microscopy (FE-SEM) images of the pores were obtained.…”

Section: Resultsmentioning

confidence: 96%

Frontal polymerization-triggered simultaneous ring-opening metathesis polymerization and cross metathesis affords anisotropic macroporous dicyclopentadiene cellulose nanocrystal foam

Park

Kwak

2022

Commun Chem

View full text Add to dashboard Cite

Multifunctionality and effectiveness of macroporous solid foams in extreme environments have captivated the attention of both academia and industries. The most recent rapid, energy-efficient strategy to manufacture solid foams with directionality is the frontal polymerization (FP) of dicyclopentadiene (DCPD). However, there still remains the need for a time efficient one-pot approach to induce anisotropic macroporosity in DCPD foams. Here we show a rapid production of cellular solids by frontally polymerizing a mixture of DCPD monomer and allyl-functionalized cellulose nanocrystals (ACs). Our results demonstrate a clear correlation between increasing % allylation and AC wt%, and the formed pore architectures. Especially, we show enhanced front velocity (vf) and reduced reaction initiation time (tinit) by introducing an optimal amount of 2 wt% AC. Conclusively, the small- and wide-angle X-ray scattering (SAXS, WAXS) analyses reveal that the incorporation of 2 wt% AC affects the crystal structure of FP-mediated DCPD/AC foams and enhances their oxidation resistance.

show abstract

Self Organization in Synthetic Polymeric Systems

Cited by 10 publications

References 50 publications

Frontal Polymerizations: From Chemical Perspectives to Macroscopic Properties and Applications

Frontal Polymerizations: From Chemical Perspectives to Macroscopic Properties and Applications

Anisotropic Foams via Frontal Polymerization

Frontal polymerization-triggered simultaneous ring-opening metathesis polymerization and cross metathesis affords anisotropic macroporous dicyclopentadiene cellulose nanocrystal foam

Contact Info

Product

Resources

About