Reticulitermids were significantly more likely to discover subterranean baits connected by physical guidelines than freestanding baits under both laboratory and field conditions. In the laboratory, subterranean termites built significantly longer tunnels adjacent to cellulosic guidelines than plastic guidelines. In the field, all guideline materials were equally effective at directing tunneling activity. Reticulitermes spp. workers were tested to determine their preferred substrate temperature. The preferred range for Reticulitermes spp. workers was found to be 18 to 27 degrees C. A laboratory bioassay was performed to determine if Reticulitermes spp. aggregates within thermal shadows. Significantly more Reticulitermes spp. workers aggregated within cool thermal shadows than control areas. In a multiple choice bioassay, mean consumption was higher for paper baits treated with fructose, galactose, glucose, raffinose, sucrose, trehalose and uric acid than for control baits. In a multiple choice bioassay, mean consumption was significantly lower for baits treated with arbutin, and most amino acids than for control baits. In the no-choice bioassay, the amount of paper bait consumed did not differ significantly for any of the treated baits tested and control baits. / Ph. D.

A series of RF plasmas was chosen to modify the surface chemical composition of Hercules IM7 carbon fibers. A two-liquid tensiometric method was used to determine the surface energy parameters y(ds) and I(psf) of the fibers. An XPS analysis of air and argon plasma treated fibers indicated a significant surface oxidation of the fibers which translated into low y(ds) values and high I(psf)values. An ammonia plasma was shown to remove an outer layer from the surface of the fibers. It also increased y(ds) compared to as-received fibers without affecting the non-dispersion (IPsf) XPS results indicated that methane and ethylene plasmas deposited a layer of low surface energy hydrocarbon on the fiber surface. A trifluoromethane plasma and a tetrafluoromethane plasma introduced a significant amount of fluorine containing groups in the fiber surface in the form of a fluorinated plasma polymer in the first case and through direct attack of the fiber surface by fluorine atoms in the second case. The surface chemical composition and the surface energy parameters of two series of commercially treated carbon fibers were also determined and compared to the results on IM7 carbon fibers. The adhesion of carbon fibers to polyethersulfone (PES) was measured by using the microbond pull-out test, and compared to the adhesion of the same fibers to an epoxy resin. The load required to debond the microdroplet was used as a measure of the bond strength. The data were also analyzed in terms of interfacial fracture energy accordIng to the model developed by Jiang and Penn (1992). The microbond pull-out test results showed no significant relation between the fiber surface chemical composition or the fiber surface energy, and the adhesion to PES. However, plasmas which have a strong ablative character such as the ammonia and the tetrafluoromethane plasmas did improve the fiber-PES adhesion, when compared to as-received fibers. The study of the fiber-epoxy systems revealed that a chemical effect contributed to the adhesion improvement but to a lesser extent than the "cleaning" effect of the surface treatment. The results support the two part mechanism proposed by Drzal and extend its application to carbon fiber-thermoplastic systems, but in this case the chemical effect is minimal. / Ph. D.

The concept of employing engineering thermoplastics as toughness modifiers for Bismaleimide resins was utilized to improve the fracture toughness properties of these important materials, which have applications as matrix resins for high performance composites. Modifier molecular weight, end group functionality, backbone structure and weight percent incorporation were all studied with respect to their influence on K_lc, fracture toughness properties. Increases in fracture toughness were created with thermoplastic oligomers without sacrificing high temperature properties and desirable hot-melt processing conditions. Investigations were also made to study the morphological features that develop within these modified thermosets and their resistance to specific environments. In addition, unidirectional carbon fiber composites were prepared and their mode I and II strain energy release rates measured. Respectable increases in the interlaminar fracture toughness were obtained, 15 and 20 percent by weight loadings of maleimide terminated polysulfone modifiers yielded G_lc values of 489±25 and 734±10 J/m² respectively, a substantial improvement over the control value of 359±17 J/m². Laminates were prepared using carbon fibers that had been investigated in terms of their surface energies using Inverse Gas Chromatography. It was illustrated how this technique could distinguish between the acid-base properties of fibers possessing different degrees of proprietary surface treatments. Fiber composites containing both contrasting and subtle changes at the fiber-matrix interphase were prepared and their mechanical properties evaluated using a variety of test methods. Dramatic increases in laminate properties were measured for composites possessing contrasting interphases. Furthermore, the mode II fracture toughness test was sensitive to interphase differences; however, the mode I fracture toughness test was not. Specimens subjected to the new Continuous Ball Indentation test method (meso-indentation) were compared with single fiber micro-indentation test results. Differences were detected in composites prepared using untreated and surface treated fibers. The new method was also sensitive to changes in matrix ductility. Certain anomalies that were noted to be surprising from micro-indentation measurements were not present in the meso-indentation test results. These observations brought to light certain limitations found within the micro-indentation test, but further supported the new test method as a potential technique for fiber-matrix interphase evaluation. / Ph. D.

Injection Molding The effects of partial miscibility on the mechanical properties and morphology of thermotropic liquid crystalline polymer blends were investigated in this part of the work. Blends of an immiscible (Vectra A900) and partially miscible (HX1000) thermotropic liquid crystalline polymer (TLCP) with a polyetherimide (PEI) were used in the investigations. The blends were injection molded into mini-tensile bars and rectangular plaques, and their mechanical properties were evaluated. Interfacial, rheological, and morphological properties along with molecular orientation analysis were carried out in order to explain the mechanical properties of the blends. Mechanical tests showed that both the tensile and flexural modulus deviate positively from the law of mixtures. However, for the PEI/HX1000 system the deviation from the law of mixtures appeared at lower TLCP concentrations compared to the PEI/Vectra A900 system. It was found that the tensile modulus correlated well with the structure developed during injection molding. Morphological tests show that finer higher aspect ratio TLCP fibers developed in the PEI/HX1000 system relative to the PEI/Vectra A system. In addition, both blends showed a maximum in the tensile modulus at 90 wt% TLCP. Rheological tests indicated that for TLCP-rich compositions, a higher viscosity was observed for the blends in comparison to the neat TLCPs. Therefore, due to a greater viscosity, higher magnitudes of stresses, consequently inducing a higher degree of molecular orientation, were experienced by the blends relative to the neat TLCPs. Although partial miscibility seemed to affect more strongly the stiffness of the in situ composite, the ultimate properties of the TLCP strongly dominated the ultimate properties of the PEI/TLCP composite. Mechanical tests showed that the ultimate properties of Vectra A were at least twice those of HX1000. Consequently, for TLCP-rich compositions, higher values of toughness, elongation at break and tensile strength were observed for PEI/Vectra A blends compared to PEI/HX1000 blends. The study presented here seems to suggest that the selection of a TLCP to reinforce a polymeric matrix is not only dependent upon whether partial miscibility or compatibility between the TLCP and matrix polymer exist, but also on the mechanical properties of the TLCP. Shearfree Elongational Deformation The effects of uniaxial, planar and biaxial deformations on the morphology and mechanical properties of bends of a polyetherimide with thermotropic liquid crystalline polymers were investigated in this part of the work. Extruded sheets and molded plaques of PEI/Vectra A and PEI/HX1000 blends were used in the studies. In the case of injection molded plaques, in which the initial morphology was that of fibers and droplets, the direction of the applied deformation relative to the initial direction of the TLCP fibrils was an important factor in affecting the resultant morphology and corresponding mechanical properties of the blends. If the direction of the applied uniaxial deformation was parallel to the initial fiber direction, the deformation tended to increase the average aspect ratio of the TLCP fibers and mechanical properties were enhanced along the direction of deformation. However, if the deformation was applied transverse to the initial fiber direction, the fibers tended to follow the deformation and a 90° rotation was observed. In terms of mechanical properties, an increase in the transverse direction properties accompanied by a reduction in the flow direction properties followed the realignment of the fibers. In addition, equal flow and transverse mechanical properties appeared at 0.5 units of transverse uniaxial strain. Planar deformation led to the spreading of the fibers in the plane of deformation and a ribbon-like morphological structure developed. However, at comparative magnitudes of planar strains, transverse planar compression tends to promote a greater spreading of the fibers relative to planar compression applied parallel to the initial direction of the fibers. In addition, planar stretching applied in a direction perpendicular to the initial direction of the TLCP fibers was effective in reducing the mechanical anisotropy of the molded plaques. Samples showing equal flow and transverse properties were obtained when planar strains greater than 0.5 units were applied in a direction perpendicular to the initial direction of the fibers. In the case of extruded sheets, in which the initial morphology was that of drops, it appeared that partial miscibility was an important factor in affecting the final morphology of the sheet. For the immiscible PEI/Vectra A system, longer and more stable TLCP fibrils were found compared to PEI/HX1000 system. It is believed that, due to lower interfacial tension, stress induced fiber breakup occurred during stretching of the PEI/HX1000 blend. Thermoforming of In Situ Composites The use of in situ thermoplastic composites based on blends of a polyetherimide with an amorphous and a semicrystalline liquid crystalline polymer in the thermoforming process was explored in this part of the work. Injection molded and extruded samples, in which the initial morphology of the dispersed TLCP phase was either in the form of fibers or droplets, were subjected to thermoforming. It was found that in the case where the initial morphology of the dispersed TLCP phase was that of droplets, the elongational stresses generated during forming were capable of deforming the TLCP phase into fibers, and the aspect ratio of the fibers was increased with depth of draw. However, when the initial morphology of the the TLCP phase was in the form of fibers, then the relative alignment of the fibers with respect to the forming direction was an important factor in affecting the final structure of the TLCP phase in the formed tray. When the fibers were aligned parallel to the forming direction, the elongational strains generated during forming tended to further increase the aspect ratio of the fibers. In the case where the initial TLCP fibers were aligned transversely to the forming direction, the fibers tended to spread into a ribbon-like structure after forming. Pre-stretching of the samples prior to thermoforming tended to contribute to an increase in the aspect ratio of the TLCP fibers. As a result, an enhancement in the deflection resistance of the prestretched/formed samples was observed. In situ thermoplastic composites seemed to be advantageous compared to glass reinforced thermoplastics in thermoforming applications. The elongational stresses generated during forming tended to deform the TLCP phase into a specific morphology. Depending on the relative direction of the deformation, either fibers or a ribbon-like structure may be developed. This is in contrast to glass reinforced PEI, in where breakage of the glass fibers occurred upon forming, which may contribute to a reduction in the mechanical performance of glass reinforced materials. / Ph. D.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Thermoplastic composites (TPCs) have shown significant advantages over thermosetting composites. They have only been put into use recently and global knowledge in TPCs is often proprietary, therefore a study into the application, processing and properties is of importance. The aim of the study is to contribute knowledge in TPCs for South African industry and academic institutions. This thesis studies continuous fibre reinforced thermoplastics (CFRTPs), focussing on the autoclave processing of commingled CFRTPs. A literature study provided background knowledge to CFRTPs regarding processing techniques and mechanics. Flexural testing and impact testing were performed on a variety of CFRTPs and thermosetting composites (TSCs). These tests were performed to further understand CFRTPs as well as to compare CFRTPs and TSCs. The flexural testing revealed that CFRTPs have comparable strength and stiffness to the TSCs that were tested. They also revealed that pre-consolidated sheets showed better and more consistent properties than sheets made from commingled fabric. The impact testing revealed that the tested CFRTPs and TSCs had similar impact resistance even though thermoplastic composites are supposed to be more impact resistant. The tests also showed that thick unreinforced thermoplastics had much higher impact resistance than the reinforced materials. Manufacturing experiments were performed to establish sound processing methods of CFRTPs. It was realised here that the high temperatures required to process the materials require specific processing consumables and tooling. The experiments began by processing flat panels in a convection oven with vacuum bagging techniques. They then progressed to autoclave processing of parts with complex geometry. An airline seat backrest was chosen as the case study in the application of CFRTPs. This application requires structural strength and stiffness and also has strict fire, smoke, toxicity and heat release (FSTH) requirements. Its geometry was sufficiently complex to demonstrate the use of commingled CFRTP material. Backrests were made from both CFRTPs and TSCs so that a comparison could be made between the two types. The backrest was modelled using finite element methods (FEM) to determine an adequate lay-up. This lay-up was then used for both the CFRTP and TSC backrests to ensure similarity between the backrests of both materials. LPET (modified polyethylene terephthalate) was the chosen thermoplastic matrix as it was more attainable than PPS (polyphenylene sulphide) CFRTPs. The backrests of both materials were manufactured in an autoclave with a vacuum bag method and then assembled using adhesives and bonding jigs. Testing revealed that the stiffness and mass of the CFRTP backrests were very similar to the epoxy backrests. This implies that commingled CFRTPs can replace the use of TSCs in similar applications. A basic cost comparison was also performed to compare the manufacture of CFRTP backrests to TSC backrests. Further work is needed to optimise processing time of these materials to make them more competitive with TSCs. The processing time of commingled materials will probably never be as quick as that of press formed pre-consolidated sheets. Their ability to be formed into more complex parts does however make their use advantageous. / AFRIKAANSE OPSOMMING: Termoplastiese saamgestelde materiale (Engels: thermoplastic composites (TPCs)) toon beduidende voordele bo termoverhardbare saamgestelde materiale. Hulle word eers sedert onlangs benut en algemene kennis in TPCs is dikwels patentregtelik, dus is ’n studie van die aanwending, prosessering en eienskappe daarvan van belang. Die doel van hierdie studie is om ’n bydrae te lewer tot die kennis van TPCs vir die Suid-Afrikaanse industrie en akademiese instellings. Hierdie tesis ondersoek kontinue veselversterkte termoplastieke (Engels: continuous fibre reinforced thermoplastics (CFRTPs)) en fokus op die outoklaafprosessering van vermengde (Engels: commingled) CFRTPs. ’n Literatuurstudie het die agtergrondkennis rakende die prosesseringstegnieke en meganika van CFRTPs verskaf. Buigtoetsing en impaktoetsing is op ’n verskeidenheid CFRTPs en termoverhardbare saamgestelde materiale (Engels: thermosetting composites (TSCs)) uitgevoer. Hierdie toetse is uitgevoer om CFRTPs beter te verstaan asook om CFRTPs en TSCs te vergelyk. Die buigtoetsing het onthul dat CFRTPs ooreenstemmende sterkte en styfheid het as die TSCs wat getoets is. Dit het ook getoon dat vooraf-gekonsolideerde plate beter en meer konsekwente eienskappe getoon het as plate wat van vermengde materiaal gemaak is. Die impaktoetsing het onthul dat die CFRTPs en TSCs wat getoets is soortgelyke impakweerstand gehad het, selfs al is termoplastiese saamgestelde materiale veronderstel om meer impakweerstand te toon. Die toetse het ook getoon dat dik onversterkte termoplastieke veel hoër impakweerstand gehad het as die versterkte materiale. Vervaardigingseksperimente is uitgevoer om betroubare prosesseringsmetodes vir CFRTPs vas te stel. Daar is besef dat die hoër temperature wat vereis word om die materiale te prosesseer ook spesifieke prosesseringsverbruiksware en -gereedskap benodig. Die eksperimente het begin met die prosessering van reguit panele in ’n konveksie-oond met vakuumsaktegnieke. Daar is toe aanbeweeg na die outoklaafprosessering van onderdele met komplekse geometrie. Die rugleuning van ’n vliegtuigsitplek is gekies as die gevallestudie in die gebruik van CFRTPs. Hierdie toepassing vereis strukturele sterkte en styfheid en is ook onderhewig aan streng vereistes t.o.v. brand, rook, toksisiteit en hittevrystellimg (Engels FSTH). Die geometrie daarvan was kompleks genoeg om die gebruik van vermengde CFRTP-materiaal te demonstreer. Rugleunings is gemaak van beide CFRTPs en TSCs sodat ’n vergelyking tussen die twee tipes gemaak kon word. Die rugleuning is gemodelleer deur eindige element metodes (EEM) te gebruik om ’n aanvaarbare oplegging te bepaal. Hierdie oplegging is toe gebruik vir beide die CFRTP en TSC rugleunings om die gelykvormigheid tussen die rugleunings van beide materiale te verseker. LPET (Engels: modified polyethylene terephthalate) was die gekose termoplastiese matriks aangesien dit meer verkrygbaar was as PPS (Engels: polyphenylene sulphide) CFRTPs. Die rugleunings van beide materiale is vervaardig in ’n outoklaaf met ’n vakuumsakmetode en toe geintegreer deur die gebruik van kleefstowwe en setmate. Toetsing het getoon dat die styfheid en massa van die CFRTP rugleunings baie soortgelyk was aan die epoksie rugleunings. Dit impliseer dat vermengde CFRTP die plek van TSCs in soortgelyke gebruike kan inneem. ’n Basiese kostevergelyking is ook gedoen om die vervaardiging van CFRTP-rugleunings teenoor TSC-rugleunings te vergelyk.

Thesis (M.Tech.: Mechanical Engineering)-Dept. of Mechanical Engineering, Durban University of Technology, 2007 xiii, 101 leaves / Polymer nanocomposites may be defined as structures that are formed by infusing layered-silicate clay into a thermosetting orthermoplastic polymer matrix. The nanocomposites are normally particle-filled polymers for which at least one dimension of the dispersed particles is in nanoscale. These clay-polymer nanocomposites have thus attracted great interest in industry and academia due to their exhibition of remarkable enhancements in material properties when compared to the virgin polymer or conventional micro and macro-composites. The present work describes the synthesis, mechanical properties and morphology of nano-phased polypropylene structures. The structures were manufactured by melt- blending low weight percentages of montmorillonite (MMT) nanoclays (0.5, 1, 2, 3, 5 wt. %) and polypropylene (PP) thermoplastic. Both virgin and infused polypropylene structures were then subjected to quasi-static tensile tests, flexural tests, micro-hardness tests, impact testing, compression testing, fracture toughness analysis, dynamic mechanical analysis, tribological testing. Scanning electron microscopy studies were then conducted to analyse the fracture surfaces of pristine PP and PP nanocomposite. X-ray diffraction studies were performed on closite 15A clay and polypropylene composites containing 0.5, 1, 2, 3 and 5 wt. % closite 15A nanoclay to confirm the formation of nanocomposites on the addition of organo clays. Transmission electron miscopy studies were then performed on the PP nanocomposites to determine the formation of intercalated, exfoliated or agglomerated nanoclay structures. Analysis of test data show that the mechanical properties increase with an increase in nanoclay loading up to a threshold of 2 wt. %, thereafter the material properties degrade. At low weight nanoclay loadings the enhancement of properties is attributed to the lower percolation points created by the high aspect ratio nanoclays. The increase in properties may also be attributed to the formation of intercalated and exfoliated nanocomposite structures formed at these loadings of clay. At higher weight loading, degradation in mechanical properties may be attributed to the formation of agglomerated clay tactoids. Results of XRD, transmission electron microscopy studies and scanning electron microscopy studies of the fractured surface of tensile specimens verify these hypotheses.

This study is dedicated to thermoplastic composite joints obtained by an electrical resistance welding procedure. This welding process consists in joining two substrates with an electrical resistor which acts as a heating element melting the polymer substrates. The substrates considered herein are 2mm thick 7-layer hybrid composites, with the following stacking sequence ([0°/90°]G, [0°/90°]C, [45°]C, [0°/90°]C, [45°]C, [0°/90°]C, [0°/90°]G), where G and C denote plies with PPS matrix reinforced by continuous glass or carbon bres, respectively. The heating element is a stainless metallic grid surrounded by two PPS amorphous lms. For a better understanding of the the time evolution of the temperature eld in the welded zone, a heat transfer model was developed in nite element code Abaqus®. The prediction capabilities of the numerical tool were validated by comparing the numerical results with thermocouple measurements. The thermal properties required by the nite element model, viz. the specic heat and the thermal conductivities, were identied from DSC tests and from an inverse identication procedure, respectively. The inverse identication procedure is based on a Levenberg-Marquart algorithm applied to the analysis of specic experiments instrumented with thermocouples and an infra-red camera. Thermal or/and mechanical analyses of anisotropic composite laminates can lead to high computational costs even for linear analyses. Proper Generalized Decomposition constitutes a promising tool to reduce computational costs for multi-dimensional problems such as multi-parametric problems typical of manufacturing process simulations and/or problems with dierent length scales typical of composite laminates. To demonstrate its capabilities and its eciency {including in terms of computation costs for small size problems- PGD technique is applied to the solution of an axisymmetric heat transfer problem. Specimens were manufactured (with a laboratory welding machine designed and built during this study) with dierent processing parameters - eating element geometry, intensity of the electrical current, time evolution of the pressure. DCB specimens were tested to characterize the mechanical toughness under mode I. The analysis with the compliance method of the tests results exhibits two non-negligible energy dissipation mechanisms, related to crack creation and localized plastic deformation, respectively. An original model developed within the internal variable thermodynamics framework is proposed and used to describe the R-curves representative of the ductile behaviour of the DCB specimens. A rst sensitivity analysis of the processing parameters on the joint fracture toughness exhibits the key role of the pressure applied onto the joint during the cooling phase of the welding process. / Este estudo é dedicado a juntas de compósitos termoplásticos soldadas pelo processo de soldagem por resistência elétrica. Este processo consiste em unir dois substratos com um resistor elétrico que atua como um elemento de aquecimento que funde o polímero dos substratos. Os substratos considerados neste trabalho são laminados compósitos híbridos, constituídos de 7 camadas que totalizam 2 mm de espessura, com a seguinte sequencia de empilhamento ([0°/90°]G, [0°/90°]C, [45°]C, [0°/90°]C, [45°]C, [0°/90°]C, [0°/90°]G), onde G e C denotam camadas de PPS reforçadas com fibra de vidro ou carbono, respectivamente. O elemento de aquecimento utilizado é uma malha metálica de aço inoxidável entre dois filmes de PPS (amorfos). Para um melhor entendimento do histórico do campo de temperatura na região soldada, um modelo de transferência de calor foi desenvolvido no pacote de elementos nitos Abaqus®. As capacidades de predição de temperatura do modelo computacional foram validadas a partir da comparação com resultados experimentais de termopares. As propriedades térmicas do modelo em elementos nitos, viz. o calor específico e as condutividades térmicas, foram identificadas a partir de ensaios DSC e de um procedimento de identificação inverso, respectivamente. O procedimento de identificação inversa foi baseado no algoritmo de Levenberg-Marquart aplicado na análise de experimentos específicos intrumentados com termopares e com uma câmera infra-vermelha. A análise térmica ou/e mecânica de laminados compósitos anisotropos podem apresentar elevados cusos computacionais, mesmo para análises lineares. A técnica PGD (Proper Generalized Decomposition) é uma ferramenta promissora na redução de custos computacionais de problemas multidimensionais, tópicos de simulação do processo de manufatura, e/ou problemas multi-escalas, tópico de laminados compósitos. Para demonstrar sua capacidade e sua eficiência, a técnica PGD é aplicada na solução de um problema axissimétrico de transferência de calor. Corpos-de-prova foram fabricados (com a máquina de soldagem laboratorial desenvolvida e construída durante este estudo) com diferentes parâmetros de processamento - geometria do elemento de aquecimento, intensidade da corrente elétrica, histórico de pressão. Corpos-de-prova DCB foram testados para caracterizar a resistência mecânica à propagação de trinca em modo I. A análise com o método da exibilidade dos resultados mostram dois mecanismos predominantes de dissipação de energia, correlatos com a criação da trinca e a localização de deformação plástica, respectivamente. Um modelo original desenvolvido baseado nas variáveis internas termodinâmicas é proposto e usado para descrição das curvas-R representativas do comportamento dúctil dos corpos-de-prova DCB. Uma primeira análise de sensibilidade da resistência à fratura ao variar os parâmetros de processamento mostra que a pressão aplicada na junta durante a etapa de resfriamento desempenha papel fundamental na resistência final da junta.

Graduation date: 1999

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Title from PDF title page (viewed Feb. 1, 2010). Additional advisors: Derrick R. Dean, Gregg M. Janowski, Selvum (Brian) Pillay (ad hoc). Includes bibliographical references (p. 76-82).

D. Tech. Chemical, Metallurgical and Materials Engineering / Aims to develop a thermoplastic matrix-based composite with a view to identifying the most suitable combinations of locally available natural fibres and matrices, which meet some basic requirements (e.g., fire and moisture resistance) for the structural and non-structural materials utilised in the building and construction industries.This general goal is divided into three distinct aims: 1. Examine the chemical surface modification of natural fibres (flax, hemp, pineapple and sisal) using water glass (WG). The study investigates the effect of WG treatment on the mechanical and thermooxidative properties of natural fibres. 2. To produce untreated and WG-treated short sisal/polypropylene (with or without maleic anhydride-grafted-polypropylene) compounds using the injection moulding process. The study also investigates the failure behaviour of the composites produced by the tensile-acoustic emission technique as well as the thermal and water absorption characteristics thereof. 3. To produce untreated and WG-treated nonwoven sisal/polypropylene (with or without maleated polypropylene) composites by using the compression moulding process. The study also investigated the fire resistance characteristics of composite materials.