Modification on natural fiber and its effect on the mechanical properties of polymer composites

Abstract

Natural fiber composites combine good me<:harlicalproperties with a low specific mass and ,eem to be an al!emative matenal to glass-fiber reinforced pbstics in some lechnio1al apphoatio[\ The m.in purpose of addmg cellulose-based filler to thennoplaslics is to redule cost! unil volume and improve stiffness. This project deals w!th charactenzation of differe~t types of !reated and untreated jute fibers, 10 fabricate natural fiber-reinforced POlym~r I compo'lle, and 10 mvestigate adhesion and mterfacial bond characteristics wah a "iew to optimizi"g key properties, Different types of jule were collecled from Bangladesh Jule Re,ea",h InS!ltute, These Jute types are raw jute, retted Jute, scoured jute, Thc,e fiber< ale lrealed with maleic anhydrate and sodIUm hydroXIde, Then the untreated and lrealed fibel. of three types of fibers are characterized, TenSile slrength, linear denSlly, charaoteristihs Slrength, weibull modulus are determined by following slandard, Retted jute fiber possess~s greater strenglh lhan that of raw jule fiber Because lhe fiber surface of relled jutc ale I smoother lhan that of raw jute Any lypes of treatment natural (fetting), chemLcal (Maleic Anhydnde, Sodium Hydroxide) causes weighl loss of fiber. \'ihich leads to decrease in diameter of mdividual fiber and decrease m hnear dcn"ty of fiber, Bolh MAH and NaOH, lrealment increase the strength of jute fiber Bu! m caSe of};aOIl lreatmentthe increase is brger. Both types of lrealed and untreated fibers thermally charactorized by Differenltal Scanmng caioriemetry (DSC) and Thermo gravimelric analysi, (TGA). Scanning eleclron mieroscoJy techm4ues used 10lme'ligate the slructure and surface morphology of untreated and treate1d jute fibers, Waler absorplion losl are carried out and the weight loss associated wllh 1)0 types of lreatment calcula!ed_ TI\e presence of roughness m case of raw jute fiber surfade srructure facila!ed e,'aporation of moisture al lower temperature. The percentaJe degradation for the CI-cellulose of retted fiber under lreated and untreated condtl'on wds ol","ys h'gher than thol of raw jule fiber. In case of NaOH treated fetted fibers. the dcellulose decomposition peak changed from endothennic 10 eXOlhermie, TI\e removal df hemicellulose during };aOH treatment leading 10 the de,lruclion of the chen"cal linkade between the conSlituents mighl have ,ome influence in inverting the a-celluloJe decompo.,itLon peak from endothemlic to e~othemlic. The untT.ated and lrealed fibers "r~ chopped 10 three definite Slze (5mm, 41llm, 2 nun), Composile, ",c fabricated by uSLn~ polypropylene as matrix malerds with tiJcse ,'arlOllS types of chopped jule nbcrs by hJlI, '" pr<:ssmg Four d,fferenl volume percentages of fibers are incorporated Mechanical characterizauon of Ihese fabricaled composites was done using Universal Testing Machine, ASTM D3039 test method was followed for lensile lest of composite specimen; ASTM D790 test method was followed for flexural or three point bend tesl of composite' Composite ",ith larger liber size shows greater strenglh Overaii tomposlle lensile stresses are lower lhan that of reference polymer. MAH trealed jule fiber compo,ites showed lower stress than that of unlremed jute polypropylene composites and NaOH lrealcd jUle polH,ropylene composiles. Tensile moduli of all composiles are b'!Cater lhan lhat of reference polymer. In ca,e ofMAH lrealment the compo,ile shows better tensile modulus. Failure surface and failure prome "ere observed under a scanning electron microscope (SEM) to reveal (he posl failure characteristics of dIe compoSlte body. Predominanl mode of faLlure for mdlVidual loading eondllion of lh.,,, composite, were analyzed comparing the faLiure prof Lie.Scanning electron micro,copy ,haws that lhere are fiber pull out in lensile failure ,urface and polymeric residlle on fiber surface, Failllre mode also interface dependent. Dunng tensile test lhe fibers Ihat lie perpendicular to lheload dirctllons aCleda, flaw and non_loadbearing component of compo,ite,. Flexure stress of Ihree types of compOst!es are lower that that of reference polymer, MAH trealed jute fiber composites ,howed lower Slress than lhat of untreated jute polypropylenc composlles and NoOH treated jute polypropylene composites. Flexure ,tiffness increase 10a considerable amounl lhan Ihat of reference polymer. Compositcs arc also lhermally analyzed u,ing DSC and TOA. TOIDTO, DSC curvC of composilcS shows Ihal final degradation lemperaturcs of composlles are higher lhan lhal of Jute fibers, MAH treated jule polypropylene composiles showed higher decomposltion lcmperarure for l" peak whereas NaOH trealmonllowers this pe.k temperature for retted fiber. All compostre, showed lower 2"' peak temperalure than Ihat of Jute fibers,