PROCESSING AND CHARACTERIZATION OF POLYETHYLENE TEREPHTALATE GLYCOL-MODIFIEDEPOXY CARBON NANOTUBES-GLASS FIBERS COMPOSITES
Author
Miranda Maduro, Marco Aurelio
Term
4. term
Education
Publication year
2013
Pages
82
Abstract
Glasfibre bruges ofte til at gøre plast stærkere i kompositmaterialer, for eksempel i flydele, raketmotorhylstre og biler. Hvor godt materialet klarer sig, afhænger i høj grad af, hvor effektivt belastninger overføres fra plasten (matrix) til fiberen, og derfor er grænsefladen mellem de to materialer afgørende. En idé er at dyrke kulstofnanorør på fiberoverfladen, fordi de bittesmå rør kan vikle sig ind i polymerkæder og dermed give en mere robust fysisk binding. I dette arbejde blev kulstofnanorør dyrket på overfladen af kul- og glasfibre ved kemisk dampdeponering (CVD) af ethylen under forskellige betingelser. De resulterende fiber–kulstofnanorør-hybrider blev karakteriseret med energidispersiv røntgenanalyse (EDX), scanning elektronmikroskopi (SEM), Raman-spektroskopi og termogravimetrisk analyse (TGA). Udvalgte glasfibre med dyrkede kulstofnanorør blev derefter indlejret i polyethylenterephthalat-glycol (PETG) og epoxyharpiks. Effekten af kvaliteten og mængden af nanorør på bindingen mellem fiber og matrix i PETG- og epoxykompositter blev vurderet med enkeltfiber-fragmenteringstests (SFFT), mikroskopi og fotoelasticitetsanalyser og sammenlignet med sizebehandlede fibre (en tynd overfladebelægning kendt som sizing). For PETG-kompositterne viste resultaterne, at sizebehandlede fibre gav bedre fiber/matrix-adhæsion end fibre med kulstofnanorør på overfladen. Ændringer i nanorørskvalitet eller -mængde gav ikke nogen væsentlig forskel i grænsefladestyrke for PETG. I epoxy så tilstedeværelsen af kulstofnanorør på fiberoverfladen derimod ud til at forbedre bindingen mellem fiber og matrix. Denne observation er dog kun baseret på mikroskopi og fotoelasticitet.
Glass fibers are widely used to strengthen plastics in composite materials, such as aircraft parts, rocket motor cases, and automobiles. Mechanical performance depends on how efficiently loads are transferred from the plastic (matrix) to the fiber, making the fiber–matrix interface critical. One approach is to grow carbon nanotubes (CNTs) on the fiber surface, because these tiny tubes can tangle with polymer chains and create a stronger physical grip between the two phases. In this work, CNTs were grown on the surfaces of carbon and glass fibers by chemical vapor deposition (CVD) of ethylene under different conditions. The resulting fiber–CNT hybrids were characterized by energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), Raman spectroscopy, and thermogravimetric analysis (TGA). Selected CNT-bearing glass fibers were then embedded in polyethylene terephthalate glycol (PETG) and epoxy resin. The influence of CNT quality and amount on fiber/matrix interfacial strength in PETG and epoxy composites was evaluated using single fiber fragmentation tests (SFFT), microscopy, and photoelasticity, and compared with fibers treated with sizing (a thin surface coating). For PETG composites, the size-treated fibers showed better fiber/matrix adhesion than fibers with CNTs grown on their surfaces. Varying the quality or amount of CNTs did not lead to significant differences in interfacial strength for PETG. In epoxy, the presence of CNTs on the fiber surface appeared to enhance interfacial bonding between fiber and matrix. This observation is based only on microscopy and photoelasticity.
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