Polydopamine and Its Derivative Materials: Synthesis and Promising Applications in Energy, Environmental, and Biomedical Fields

Biocomposites reinforced with natural fibers: 2000–2010

INTRODUCTION. Internal Organization of the Plant Body. Summary of Types of Cells and Tissues. General References. DEVELOPMENT OF THE SEED PLANT. The Embryo. From embryo to the Adult Plant. Apical Meristems and Their Derivatives. Differentiation, Specialization, and Morphogenesis. References. THE CELL. Cytoplasm. Nucleus. Plastids. Mitochondria. Microbodies. Vacuoles. Paramural Bodies. Ribosomes. Dictyosomes. Endoplasmic Reticulum. Lipid Globules. Microtubules. Ergastic Substances. References. CELL WALL. Macromolecular Components and Their Organization in the Wall. Cell Wall Layers. Intercellular Spaces. Pits, Primary Pit--Fields, and Plasmodesmata. Origin of Cell Wall During Cell Division. Growth of Cell Wall. References. PARENCHYMA AND COLLENCHYMA. Parenchyma. Collenchyma. References. SCLERENCHYMA. Sclereids. Fibers. Development of Sclereids and Fibers. References. EPIDERMIS. Composition. Developmental Aspects. Cell Wall. Stomata. Trichomes. References. XYLEM: GENERAL STRUCTURE AND CELL TYPES. Gross Structure of Secondary Xylem. Cell Types in the Secondary Xylem. Primary Xylem. Differentiation of Tracheary Elements. References. XYLEM: VARIATION IN WOOD STRUCTURE. Conifer Wood. Dicotyledon Wood. Some Factors in Development of Secondary Xylem. Identification of Wood. References. VASCULAR CAMBIUM. Organization of Cambium. Developmental Changes in the Initial Layer. Patterns and Causal Relations in Cambial Activity. References. PHLOEM. Cell Types. Primary Phloem. Secondary Phloem. References. PERIDERM. Structure of Periderm and Related Tissues. Development of Periderm. Outer Aspect of Bark in Relation to Structure. Lenticels. References. SECRETORY STRUCTURES. External Secretory Structures. Internal Secretory Structures. References. THE ROOT: PRIMARY STATE OF GROWTH. Types of Roots. Primary Structure. Development. References. THE ROOT: SECONDARY STATE OF GROWTH AND ADVENTITIOUS ROOTS. Common Types of Secondary Growth. Variations in Secondary Growths. Physiologic Aspects of Secondary Growth in Roots. Adventitious Roots. References. THE STEM: PRIMARY STATE OF GROWTH. External Morphology. Primary Structure. Development. References. THE STEM: SECONDARY GROWTH AND STRUCTURAL TYPES. Secondary Growth. Types of Stems. References. THE LEAF: BASIC STRUCTURE AND DEVELOPMENT. Morphology. Histology of Angiosperm Leaf. Development. Abscission. References. THE LEAF: VARIATIONS IN STRUCTURE. Leaf Structure and Environment. Dicotyledon Leaves. Monocotyledon Leaves. Gymnosperm Leaves. References. THE FLOWER: STRUCTURE AND DEVELOPMENT. Concept. Structure. Development. References. THE FLOWER: REPRODUCTIVE CYCLE. Microsporogenesis. Pollen. Male Gametophyte. Megasporogenesis. Female Gametophyte. Fertilization. References. THE FRUIT. Concept and Classification. The Fruit Wall. Fruit Types. Fruit Growths. Fruit Abscission. References. THE SEED. Concept and Morphology. Seed Development. Seed Coat. Nutrient Storage Tissues. References. EMBRYO AND SEEDLING. Mature Embryo. Development of Embryo. Classification of Embryos. Seedling. References. Glossary. Index.

Anatomy of Seed Plants

Plastic waste is currently generated at a rate approaching 400 Mt year–1. The amount of plastics accumulating in the environment is growing rapidly, yet our understanding of its persistence is very...

Degradation Rates of Plastics in the Environment

In recent years, the use of flax fibres as reinforcement in composites has gained popularity due to an increasing requirement for developing sustainable materials. Flax fibres are cost-effective and offer specific mechanical properties comparable to those of glass fibres. Composites made of flax fibres with thermoplastic, thermoset, and biodegradable matrices have exhibited good mechanical properties. This review presents a summary of recent developments of flax fibre and its composites. Firstly, the fibre structure, mechanical properties, cost, the effect of various parameters (i.e. relative humidity, various physical/chemical treatments, gauge length, fibre diameter, fibre location in a stem, oleaginous, mechanical defects such as kink bands) on tensile properties of flax fibre have been reviewed. Secondly, the effect of fibre configuration (i.e. in forms of fabric, mat, yarn, roving and monofilament), manufacturing processes, fibre volume, and fibre/matrix interface parameters on the mechanical properties of flax fibre reinforced composites have been reviewed. Next, the studies of life cycle assessment and durability investigation of flax fibre reinforced composites have been reviewed.

Flax fibre and its composites – A review

The biocompostability of natural fibre-reinforced biopolymers, also known as biocomposites, makes them attractive alternative to glass fibre-reinforced petrochemical polymers. The aim of this work is to study the capacity of flax/PLLA (poly(l-lactide)) biocomposite (20% and 30% fibres by weight) to be recycled. Mechanical properties were evaluated initially, and shown to be similar to those of glass/PP and superior to hemp/PP and sisal/PP composites. Then after repeated injection cycles tensile properties were shown to be conserved until the third cycle. Matrix degradation and fibre aspect ratio were followed using molecular weight measurements, thermal and rheological analyses, image analysis of sections and SEM fractography. These techniques revealed a lower molecular weight, lowering of glass transition temperature, reduction of fibre length, and separation of fibre bundles with injection cycles. Nevertheless, the property retention after three cycles under extreme recycling conditions (100% recycling with no added virgin polymer) indicate the promising recyclability of these materials.

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Effect of recycling on mechanical behaviour of biocompostable flax/poly(L-lactide) composites

The study of plant fibres composites is a widespread research topic; nevertheless, the reinforcement mechanism understanding of these materials must be still improved. The paper presents a study of the effect of the mechanical properties, the dispersion and the fibre/matrix interface property of elementary fibres on the tensile properties of unidirectional composites. Our work shows that the mechanical performances of unidirectional composites could be linked to those of the elementary fibres as well as to the composites microstructure. Flax fibres individualisation, linked to the homogeneity of the microstructure, is highly dependent on the fibre extraction process. The importance of the composites homogeneity has been confirmed by the Rosen model, which could be used thanks to interfacial shear strength measurements.

Effect of flax fibres individualisation on tensile failure of flax/epoxy unidirectional composite

Accelerated ageing of polylactide in aqueous environments: Comparative study between distilled water and seawater

The present study quantifies the environmental impacts of the production of hackled flax fibres destined for reinforcement of composite materials and compared with those for the production of glass fibres. The ecological advantages of flax fibres production over glass fibres are shown. Most of the environmental indicators used (climate change, acidification, non-renewable energy consumption...) are favourable to flax fibres. However the eutrophication indicator remains high, mainly due to the use and production of fertilizers. Possible optimisation is studied by means of reduction of mechanical extraction steps and chemical products use. A sensitivity analysis highlights that the calculation method used (CML2000 modified) is robust. The hypothesis of carbon dioxide sequestration influences the climate change indicator. The choice of allocation method, by weight or by economic value, has also a strong influence on the environmental impacts. Globally, the production of flax fibres appears to be an environmentally attractive alternative to glass fibres.

Antoine Le Duigou

Papers

Effect of recycling on mechanical behaviour of biocompostable flax/poly(L-lactide) composites

Effect of flax fibres individualisation on tensile failure of flax/epoxy unidirectional composite

Accelerated ageing of polylactide in aqueous environments: Comparative study between distilled water and seawater

Environmental Impact Analysis of the Production of Flax Fibres to be Used as Composite Material Reinforcement

Interfacial bonding of Flax fibre/Poly(L-lactide) bio-composites