412661 news 1433855164 1475896713 <![CDATA[Research in Auxetic Behavior of Fiber Cellulose Networks Shows Promise for New Paper Applications]]> Prateek Verma’s research indicates that cellulose-based fiber networks have auxetic properties that may be used to create novel functional and structural material designs for paper.  Auxetic materials grow fatter, not thinner, when stretched and are extremely rare in nature.  It had been previously reported that fibrous paper increased in thickness when stretched in a planar direction.

Prateek measured the thickness variation with stretch in different types of paper, including copy paper, paperboard, and softwood and hardwood handsheets, and showed their Poisson’s ratio to be negative (0 to -3.0).  Prateek and his advisors suggest that the mechanism of the auxetic response stems from the rich hydroxyl surface of the non-woven network structure of cellulose fibers.   During compressive stages of papermaking, hydrogen bonding between fibers locks them into a crumpled microstructure that expands when stretched.  Auxetic behavior arising from supramolecular surface chemistry of polymeric networks is a novel concept.

Current applications of auxetic materials include packaging, ballistic protection, filtration defouling, and prosthetic surgical implants.  Recently, researchers have also induced auxetic behavior in polyurethane foams, expanded polytetrafluoroethylene (PTFE) and ultra-high-molecular-weight polyethylene.

Prateek began his studies in 2011 at IPST, and he is seeking a PhD degree in Paper Science and Engineering within the School of Materials Science and Engineering.  His advisors are Dr. Anselm Griffin and Dr. Meisha Shofner.

]]> 2013-06-01T00:00:00-04:00 412651 image <![CDATA[Prateek Verma]]> 202351 image/jpeg Kelly B. Smith, Marketing & Communication

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