Polymer Composites and Coatings

Cross-linked Polymer Coatings

Polyester polyols are polymers with multiple ester linkages terminated by hydroxyl groups. The diversity of these polymers stems from the numerous possibilities of specific diacids, diols, and multifunctional monomers as well as a range of possible molecular weights. These cross-linked polymeric films are used extensively as protective coatings for both metallic and non-metallic substrates. Such coatings are often applied as liquids and are then cured to give a solid, densely cross-linked film. In developing the next generation of coatings, a fundamental understanding of the curing process and the resulting film properties is needed.

Researcher: Joe Tilly

The in-situ cure behavior of these coatings can be studied chemically using spectroscopic techniques, and it can be characterized in terms of mechanical property evolution using dynamic rheology. Final film mechanical properties can be characterized using an array of techniques, from dynamic mechanical analysis (bulk film) to nanoindentation (surface properties). The ultimate goal of the research is to correlate final film properties with cure behavior and understand how different parameters, specifically polymer and cross-linker chemistry, affect coating performance.

Researcher: Amulya Pervaje
Molecular modeling of this system has started from a top-down coarse-graining approach, using thermodynamic information on the monomers to build the polymer models. Experiments are characterizing the kinetics and rheology during crosslinking as well as mechanical properties of crosslinked films. With this information and by building computational models that have been experimentally validated, we correlate and predict material properties based on underlying chemistries.

Cellulose-based Aerogel Structures

Researcher: Anurodh Tripathi

Recently, we have ventured in the area of developing light-weight and robust materials from cellulose and its derivatives for environmental remediation. Through a unique combination of well-established synthesis procedures involving chemical cross-linking, careful solvent exchange to water and subsequent freeze drying, we have produced ultra-light (4.3 mg/ml) and highly porous (99.7 %) cellulose diacetate aerogels (CDA) with honeycomb morphology. These aerogels demonstrate a maximum water and oil uptake of up to 92 and 112 g/g respectively.  The honeycomb morphology provides a maximum compression strain of 92 % without failure and reach a  compressive stress of 350 kPa, for 4 w/v% CDA aerogels (4%), which is higher than that reported for cellulosic aerogels. The 4% CDA aerogel were rendered hydrophobic and oleophilic via chemical vapor deposition with an organo-silane. The modified CDA aerogel surpass their counterparts in maintaining their mechanical integrity for fast oil cleanup and efficient oil retention from aqueous media under marine conditions. These aerogels are identified as reusable and durable for a long period.

Separation of dyed kerosene oil from water using a robust and functional cellulose-based aerogel

Designing Water Repellent Coatings using Polyurethane –Polydimethylsiloxane (PU-PDMS) Copolymers

Researcher: Dr. Marius Rutkevicus

The goals of this project are to create a water-based coating that would (1) allow for composition manipulation to tailor the coating for achieving superhydrophobicity; (2) enable adhesion to a variety of substrates while maintaining the original hand; and (3) provide a durable coating that has the ability to withstand abrasion, laundering, and excessive wear. By exploiting the properties of both polyurethanes and polysiloxanes, a block co-polymer can be synthesized to achieve strong adhesion to a variety of substrates while imparting hydrophobicity and flexibility through polydimethylsiloxane segments, and water-solubility through carboxyl containing segments. The rationale behind examining such a coating formulation stems from a need to develop and understand an aqueous-based, fluorine-free liquid-repellent coating in an attempt to shift towards more environmentally friendly technologies.