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Full-Text Articles in Physical Sciences and Mathematics
Cellulose Nanofiber-Reinforced Impact Modified Polypropylene: Assessing Material Properties From Fused Layer Modeling And Injection Molding Processing, Jordan Elliott Sanders
Cellulose Nanofiber-Reinforced Impact Modified Polypropylene: Assessing Material Properties From Fused Layer Modeling And Injection Molding Processing, Jordan Elliott Sanders
Electronic Theses and Dissertations
The purpose of this research was to investigate the use of cellulose nanofibers (CNF) compounded into an impact modified polypropylene (IMPP) matrix. A IMPP was used because it shrinks less than a PP homopolymer during FLM processing. An assessment of material properties from fused layer modeling (FLM), an additive manufacturing (AM) method, and injection molding (IM) was conducted. Results showed that material property measurements in neat PP were statistically similar between IM and FLM for density, strain at yield and flexural stiffness. Additionally, PP plus the coupling agent maleic anhydride (MA) showed statistically similar results in comparison of IM and …
Water Chemistry Dynamics In Four Vernal Pools In Maine, Usa, Lydia H. Kifner
Water Chemistry Dynamics In Four Vernal Pools In Maine, Usa, Lydia H. Kifner
Electronic Theses and Dissertations
Vernal pools are small seasonal wetlands that are a common landscape feature that contribute to biodiversity in northeastern North American forests. However, even basic information about their biogeochemical functions, such as carbon cycling, is limited. Dissolved gas concentrations (CH4, CO2) and other water chemistry parameters were monitored weekly at the bottom and surface of four vernal pools in central and eastern Maine, USA, from April to August 2016. The vernal pools were supersaturated with respect to CH4 and CO2 at all sampling dates and locations. Concentrations of dissolved CH4 and CO2 ranged …
Creating Renewable Tunable Polymers From Hydroxymethylfurfural, Meredith C. Allen
Creating Renewable Tunable Polymers From Hydroxymethylfurfural, Meredith C. Allen
Electronic Theses and Dissertations
The research here deals with the conversion of 5-hydroxymethylfurfural (HMF) into a tunable polymer. HMF is a known derivative that can be acquired from biomass via hydrolysis of cellulose followed by isomerization and finally selective dehydration. The process considered here is being developed to create tunable polymers from HMF and involves several different steps, three of which are covered here. The first step, an etherification, is the reaction of HMF with an alcohol. This step is significant because in this step the R-group from the alcohol is added to HMF and the branching portion formed is carried over to the …
Renewable Hydrogels From Norbornene-Functionalized Carboxymethyl Cellulose And A Short Dithiol Crosslinked Via A Thiol-Ene Reaction, Thomas Mcoscar
Renewable Hydrogels From Norbornene-Functionalized Carboxymethyl Cellulose And A Short Dithiol Crosslinked Via A Thiol-Ene Reaction, Thomas Mcoscar
Electronic Theses and Dissertations
Cellulose-based hydrogels - three dimensional "solid" structures composed primarily of liquid water and held together by an interconnected polymer network - were created by first functionalizing carboxymethyl cellulose (CMC), a cellulose derivative, with carbic anhydride in a basic aqueous reaction with the intent of developing novel hydrogels from renewable materials. The product of this reaction, carbic CMC (cCMC), had a new norbornene group as a subsection of the carbic group. Norbornene is a reactive alkene structure that allows for further chemistry with cCMC, such as crosslinking. cCMC was crosslinked with 2,2'-(ethylenedioxy)diethathiol to create hydrogels using a water-soluble, UV-sensitive radical initiator …