MANUFACTURING FLAX FIBRE-REINFORCED POLYPROPYLENE COMPOSITES BY HOT-PRESSING

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4601-4606 ◽  
Author(s):  
MARC JOLLY ◽  
KRISHNAN JAYARAMAN
Keyword(s):  
Composite Materials ◽  
Hot Pressing ◽  
Mass Fraction ◽  
Fibre Length ◽  
Natural Fibre ◽  
Thermoplastic Composites ◽  
Processing Temperature ◽  
Polypropylene Composites ◽  
Flax Fibres ◽  
Fibre Degradation

The renewable characteristic of natural fibres, such as flax, and the recyclable nature of thermoplastic polymers, such as polypropylene, provide an attractive eco-friendly quality to the resulting composite materials. Common methods for manufacturing natural fibre-reinforced thermoplastic composites, injection moulding and extrusion, tend to degrade the fibres during processing. Development of a simple manufacturing technique for these composites, that minimises fibre degradation, is the main objective of this study. Flax fibres were conditioned, cut into lengths ranging from 1 mm to 30 mm with scissors and a pelletiser, and shaped into randomly oriented mats using a drop feed tower. Polypropylene in sheet form, was added to the fibres to furnish polypropylene/flax/polypropylene sandwiches with a fibre mass fraction of 25%, which were then consolidated by the hot pressing technique. Tensile, flexural and impact properties of these composite sheets were determined as functions of fibre length and processing temperature.

EFFECTS OF EXTRUSION ON FIBRE LENGTH IN SISAL FIBRE-REINFORCED POLYPROPYLENE COMPOSITES

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4607-4612 ◽  
Author(s):  
SRIDHAR PATHI ◽  
KRISHNAN JAYARAMAN
Keyword(s):  
Fibre Length ◽  
Natural Fibre ◽  
Natural Fibres ◽  
Thermoplastic Composites ◽  
Front Face ◽  
Length Variation ◽  
Sisal Fibre ◽  
Polypropylene Composites ◽  
Technology Process ◽  
Fibre Degradation

Natural fibre reinforced thermoplastic composites find a wide array of applications in the automobile, building and construction industries. These composites are mostly produced by injection moulding or extrusion through properly designed dies. During these production processes, the shear forces exerted by the screw or ram leads to the degradation of the natural fibres. A screwless extruder that minimises fibre degradation and employs a reliable and low technology process has already been developed. However, the fibre degradation caused by the screwless extruder has not been compared with that of the conventional extruders. So, this study is focused on the influence of extrusion processes on the degradation of natural fibres in thermoplastic composites. Sisal fibres of 10 mm length were extruded with polypropylene, to furnish extrudates with a fibre mass fraction of 25%, using conventional single screw and screwless extruders. Polypropylene in the extrudates was dissolved in Xylene in a Sohxlet process; the fibres that were extracted were analysed for length variations. While fibre degradation in the form of fibre length variation is similar in both cases, this can be minimised in screwless extrusion by extending the gap between the front face of the cone and the orifice plate.

Natural Fibre/Polypropylene Wrap Spun Yarns and Preforms for Structured Thermoplastic Composites

2011 ◽  
Vol 675-677 ◽  
pp. 427-430 ◽  
Author(s):  
Jin Hua Jiang ◽  
Ze Xing Wang ◽  
Nan Liang Chen
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Hot Pressing ◽  
Mechanical Performance ◽  
Great Influence ◽  
Natural Fibre ◽  
Thermoplastic Composites ◽  
Flax Fibres ◽  
Fibre Composites ◽  
Spun Yarns

In the past decade, natural fibre composites with thermoplastic matrices had attracted many composites manufactures for the superiority of lightweight and low-cost. A major challenge for natural fibre composites was to achieve high mechanical performance at a competitive price. Composites constructed from yarn and fabric structure preforms were better than composites made from random nonwoven mats. However, the twist structure of conventional ring spun yarns prevented the full utilization of fibre mechanical properties in the final composites. In this paper, the wrapped yarns were produced by wrap spun method with flax and polypropylene (PP), in which all flax fibres were twistless, then woven to be fabric preforms. The PP fibres served as a carrier for flax fibres during processing and became the polymer matrix in the final composites. The homogenous distribution of fibre and thermoplastic matrix in preforms could be achieved before hot pressing, so that not lead to impregnate difficultly, and prevented damage to the reinforced nature fibres during processing. Composites made from the wrapped yarn demonstrated significant tensile and peeling properties. The fabric structures (include plain, twill, and basket weave) and yarn tensile orientation (in 0°, 90°, 45°), had great influence on tensile strength and elongation of preforms. The cavity thickness of hot pressing mould had different influence on the tensile strength and peeling strength of thermoplastic composites, and the mechanical properties were superior when the thickness was 0.8-1.2 mm. The microstructure of thermoplastic composites showed uniform infiltration between layers, and had good bonding interface between flax fibre and PP matrix in composites.

scholarly journals Better Wettability of Pandanus Utilis Alkaline Treated Fibres Tead to Higher Tensile Strengths of Composites.

2021 ◽  
Author(s):  
Laurent L'Entete ◽  
Hareenanden Ramasawmy
Keyword(s):  
Tensile Strength ◽  
Composite Materials ◽  
Carbon Footprint ◽  
Fibre Length ◽  
Natural Fibre ◽  
Engineering Properties ◽  
Aggressive Treatment ◽  
High Carbon ◽  
Reinforcing Agent ◽  
Internal Angle

Abstract Composite materials made with synthetic fibres like E-glass, Kevlar or carbon have helped to provide a wide array of products to society with specific engineering properties. However, these materials have a high carbon footprint as well as being non-biodegradable. The use of natural fibre, as a substitution to these man-made fibres, has been studied and encouraging results are being obtained.In this study, the use of ‘Pandanus utilis’ fibre as a reinforcing agent in plastic was investigated with the aim of exploring specific properties such as the tensile strength of the fibre, its wettability and the effect of fibre length after treating the fibre with two different NaOH solutions. Results have shown that better reinforcement was obtained for the composites (11.10 ± 2.53MPa) with fibres subjected to a more aggressive treatment (2.5%NaOH for 2h) compared to the composite made with fibres having maximum tensile strength (168 ± 12MPa at 0.5% NaOH for 14h), due to a better hydrophilicity of the alkaline treated fibre (87.37° internal angle). Within the range of short chopped fibre length tested (6 to 15 mm), it was shown that there was a general decrease in the tensile strength of the composite.

scholarly journals Natural-Fibre-Mat-Reinforced Thermoplastic Composites based on Flax Fibres and Polypropylene

1996 ◽  
Vol 5 (3) ◽  
pp. 096369359600500 ◽  
Author(s):  
R. Heijenrath ◽  
T. Peijs
Keyword(s):  
Maleic Anhydride ◽  
Epoxy Resin ◽  
Low Cost ◽  
Natural Fibre ◽  
Thermoplastic Composites ◽  
Unit Weight ◽  
Flax Fibres ◽  
Cost Engineering ◽  
Reinforced Thermoplastics ◽  
Fibre Matrix

Natural-fibre-mat-reinforced thermoplastics (NMTs) based on flax fibres and a polypropylene (PP) matrix were manufactured using a film-stacking method. The influence of fibre content on stiffness and strength is reported and compared with data for glass-matreinforced-thermoplastics (GMTs), including the influence of improved fibre/matrix adhesion as a result of the use of maleic-anhydride grafted PP. Additionally, unidirectional and random-flax-mat composites based on epoxy resin were manufactured as reference materials. Results indicated that NMTs are of interest for low cost engineering applications, especially when a high stiffness per unit weight is desirable.

scholarly journals An Investigation of the Effect of Processing Conditions on the Interface of Flax/Polypropylene Composites

2001 ◽  
Vol 10 (6) ◽  
pp. 096369350101000 ◽  
Author(s):  
N. E. Zafeiropoulos ◽  
C. A. Baillie ◽  
F. L. Matthews
Keyword(s):  
Surface Modification ◽  
Composite Materials ◽  
Flax Fibre ◽  
Natural Fibres ◽  
Processing Conditions ◽  
Cooling Rates ◽  
Polypropylene Composites ◽  
Flax Fibres ◽  
The Matrix ◽  
The Cost

In recent years there has been an increasing interest in using natural fibres as potential reinforcements for polymers. It is well known that the properties of composite materials are controlled by the properties of the matrix and the fibre, as well as of the interface. The most usual methods of strengthening the interface involve the application of surface modification methods on the fibres, or the application of compatibilisers in the matrix. However, it may be possible that one may achieve similar results just by simply controlling the processing conditions, and thus avoiding the application of chemicals that tend to increase the cost. In the present study the effect of cooling rates upon the interface in flax fibre/iPP composites was investigated by means of fragmentation tests. It was found that slower cooling leads to a stronger interface for two different grades of flax fibres; dew retted and green flax.

scholarly journals Critical Fibre Length and Apparent Interfacial Shear Strength of Single Flax Fibre Polypropylene Composites

1998 ◽  
Vol 7 (3) ◽  
pp. 096369359800700 ◽  
Author(s):  
M.J.A. Van Den Oever ◽  
H.L. Bos
Keyword(s):  
Shear Strength ◽  
Interfacial Shear Strength ◽  
Fibre Length ◽  
Stress Transfer ◽  
Interfacial Shear ◽  
Flax Fibre ◽  
Polypropylene Composites ◽  
Flax Fibres ◽  
Shear Yield ◽  
The Matrix

The stress transfer in, both elementary and technical, single flax fibre polypropylene composites is studied by determining the critical fibre length and the apparent interfacial shear strength. The influence of improved fibre-matrix interaction is reported and the results are compared with data from literature. The study indicates that the critical fibre length for elementary flax fibres is equal to or even higher than the flax fibre lengths found after extrusion and injection moulding processes. Furthermore, addition of maleic anhydridy modified polypropylene to the matrix results in an apparent interfacial shear strength for elementary flax fibres close to the shear yield strength of the matrix, for technical fibres the interfacial shear strength is somewhat lower.

A review on tribological behaviour of natural reinforced composites

2017 ◽  
Vol 37 (5) ◽  
pp. 349-353 ◽  
Author(s):  
H Sumithra ◽  
B Sidda Reddy
Keyword(s):  
Composite Materials ◽  
Volume Fraction ◽  
Normal Load ◽  
Fibre Length ◽  
Natural Fibre ◽  
Reinforced Composites ◽  
Tribological Behaviour ◽  
Material Parameters ◽  
Good Ability ◽  
Fibre Composites

In the past, asbestos and copper were preferred as friction materials because they have good ability to dissipate heat, but have proven to be harmful to environment. Recently, more researches are focused on non-asbestos friction composite materials due to its non-toxicity and biodegradability. Despite synthetic fibre composites having eco-friendly nature, because of its cost and pollution most of the researchers show interest on natural fibre composites. Hence, there is a need to explore the analysis on the tribologicaal behaviour of composite materials. The aim of this review is to provide overview of literature survey on the tribological characteristics such as friction, wear and lubrication of both particulate reinforced composites and fibre reinforced composites. In addition, operating and material parameters that influence tribological behaviour are also explored. Results reveal that operating parameters like normal load, sliding velocity, sliding distance, temperature and material parameters like particle size, volume fraction, fibre orientation, fibre length, surface treatment and aspect ratio have a significant effect on tribo characteristics.

scholarly journals Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls

2021 ◽  
Vol 6 (6) ◽  
pp. 82
Author(s):  
Cinthia Maia Pederneiras ◽  
Rosário Veiga ◽  
Jorge de Brito
Keyword(s):  
Modulus Of Elasticity ◽  
Drying Shrinkage ◽  
High Water ◽  
Natural Fibre ◽  
Accelerated Ageing ◽  
Flax Fibres ◽  
Aesthetic Appearance ◽  
Cement Binder ◽  
Drying Rates ◽  
Adherence Strength

One of the main functions of renders, together with the overall aesthetic appearance of the building, is the protection of the walls against external aggressive actions, such as water, salts solutions, erosion, and mechanical impacts. However, some anomalies of renders may drastically hinder their protection ability. In fact, cracking, high water permeability, and loss of adherence to the substrate of renders limit their barrier effect and favour the exposure of the substrate to external actions. The incorporation of fibres in mortars is commonly pointed out to reduce their cracking susceptibility, due to the probable enhancement in tensile strength and ductility of the composite. The use of lime in substitution of the part of the cement binder is seen as a method to reduce the modulus of elasticity and therefore enhance the resistance to cracking due to drying shrinkage. Therefore, this study investigates the wall protection-related properties of natural fibre-reinforced renders with cement-lime as a binary binder at 1:1:6 volumetric ratio. With this purpose, wool, coir, and flax fibres are used at 20% by total mortar volume and the water behaviour, cracking susceptibility, and adherence to the substrate of the mortars are assessed. Specifically, the water absorption by capillarity, drying rates, permeability to water under pressure, adherence strength, and shrinkage are evaluated. In order to evaluate the renders’ durability and therefore the durability of the protection to the walls, an artificial accelerated ageing test is performed based on heating-freezing and humidification-freezing cycles. The results indicate that the fibres’ addition reduced the shrinkage and modulus of elasticity of the mortars, which suggests lower susceptibility to cracking. The addition of fibres in mortars seemed to slightly affect their water performance and only at early ages. From the results, it was concluded that the adherence strength is not affected by the fibres’ incorporation. The fibres seem also to reduce the impacts of the ageing cycles on the mortar and the improvements provided by the fibres’ addition to the mortars’ performance remained after ageing when compared to the mortars without fibres, thus being a potential alternative to increase their durability. These aspects are particularly important for buildings, since they can extend their service life and promote their sustainability.

scholarly journals Effects of Water and Chemical Solutions Ageing on the Physical, Mechanical, Thermal and Flammability Properties of Natural Fibre-Reinforced Thermoplastic Composites

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4581
Author(s):  
Baljinder K. Kandola ◽  
S. Ilker Mistik ◽  
Wiwat Pornwannachai ◽  
A. Richard Horrocks
Keyword(s):  
Salt Water ◽  
Flexural Modulus ◽  
Moisture Sorption ◽  
Natural Fibre ◽  
Thermoplastic Composites ◽  
Wool Fibre ◽  
Poly Lactic Acid ◽  
Natural Polymers ◽  
Chemical Solutions ◽  
Pp Composites

Biocomposites comprising a combination of natural fibres and bio-based polymers are good alternatives to those produced from synthetic components in terms of sustainability and environmental issues. However, it is well known that water or aqueous chemical solutions affect natural polymers/fibres more than the respective synthetic components. In this study the effects of water, salt water, acidic and alkali solutions ageing on water uptake, mechanical properties and flammability of natural fibre-reinforced polypropylene (PP) and poly(lactic acid) (PLA) composites were compared. Jute, sisal and wool fibre- reinforced PP and PLA composites were prepared using a novel, patented nonwoven technology followed by the hot press method. The prepared composites were aged in water and chemical solutions for up to 3 week periods. Water absorption, flexural properties and the thermal and flammability performances of the composites were investigated before and after ageing each process. The effect of post-ageing drying on the retention of mechanical and flammability properties has also been studied. A linear relationship between irreversible flexural modulus reduction and water adsorption/desorption was observed. The aqueous chemical solutions caused further but minor effects in terms of moisture sorption and flexural modulus changes. PLA composites were affected more than the respective PP composites, because of their hydrolytic sensitivity. From thermal analytical results, these changes in PP composites could be attributed to ageing effects on fibres, whereas in PLA composite changes related to both those of fibres present and of the polymer. Ageing however, had no adverse effect on the flammability of the composites.

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