Bamboo fibre reinforced biocomposites: A review

Iodocompounds are highly attractive as potential intermediates for the synthesis of various organic and macromolecular molecules because of the ability of the iodine atom to be a good leaving atom. In addition, they are efficient transfer agents in radical polymerization. In fact, the ability of the iodine atom to transfer onto growing macromolecular chains allowed the development of such compounds. An important class of iodocompounds employed as chain transfer agents (CTAs) are the fluorinated iodocompounds, R FI. These compounds could be obtained in good yield by simple addition of either HI or ICl onto fluorovinylic monomers. These fluorinated CTAs enabled both initiation of the polymerization under UV, thermally or in the presence of redox catalysis, and transfer of the iodine atom onto the growing chains. Oligomers of low molar masses could then be obtained. Then, in the late 1970s, Tatemoto 1 pened the route to the iodine transfer polymerization (ITP). Hence, by using an initiating radical, iodofluorocompounds could enter in a controlled process, based on a degenerative transfer (DT). This real breakthrough was first realized with fluoroolefin monomers but was rapidly extended to other common nonhalogenated vinyl monomers. For specific applications, nonfluorinated CTAs were preferred. Some iodoalkanes, such as iodoform, were then investigated in the ITP process. Recently, reverse iodine transfer polymerization (RITP), another DT process, was discovered by us and is based on the use of molecular iodine. It was thus of interest to deeper summarize the synthesis and the use of iodinated derivatives involved in telomerization, ITP, and RITP, and these are the objectives of this review, divided in four main parts. The first part reports the syntheses of such iodocompounds, fluorinated and nonfluorinated ones. The structural requirements are also investigated for further efficient transfer reactions. The following parts describe their uses in several radical processes, i.e., telomerization, ITP, and RITP. A wide range of vinyl monomers (halogenated and nonhalogenated) have been involved in these radical techniques. Then, syntheses of well-architectured copolymers (especially block * To whom correspondence should be addressed. Tel: (0033)4 67 14 43 01. Fax: (0033)4 67 14 72 20. E-mail: bernard.boutevin@enscm.fr. 3936 Chem. Rev. 2006, 106, 3936−3962

Use of iodocompounds in radical polymerization.

Developments and new applications of UV-induced surface graft polymerizations

Dynamic mechanical and thermal analysis of vinylester-resin-matrix composites reinforced with untreated and alkali-treated jute fibres

The dynamic mechanical properties of short sisal fibre reinforced polypropylene composites containing both untreated and treated fibres have been studied with reference to fibre loading, fibre length, chemical treatments, frequency and temperature. By the incorporation of short sisal fibre into polypropylene, the storage moduli ( E ′)and loss moduli ( E ″) have been found to be increasing whereas the mechanical loss factor (tan  δ ) decreasing. The storage modulus decreases with increase in temperature. The treated fibre composites show better properties compared to untreated system. The Arrhenius relationship has been used to calculate the activation energy for the glass transition. The use and limitations of various theoretical equations to predict the tan  δ and storage modulus of the fibre reinforced plastic composites have been discussed. Cole–Cole analysis has been carried out to understand the phase behaviour of the composite samples. A master curve for the modulus of the blend is drawn by applying the time–temperature super position principle.

Dynamic mechanical properties of short sisal fibre reinforced polypropylene composites

Unidirectional (UD) composite laminates based on glass fibers (GF) and high-performance polyethylene fibers (PEF) were prepared with partially polymerized methyl methacrylate (MMA) at room temperature and then heated at 55°C (well below the softening point of PEF) for 2 hrs. The viscoelastic behavior of the composite was studied through dynamic mechanical analysis at different volume fractions of fibers. Several parameters such as storage modulus (E'), loss modulus (E), and loss factor or damping efficiency (tan ∂) were determined to be between 40 and 160°C in a resonant frequency mode. All the properties were compared between the two composite laminates. It was found that the shift of the glass transition temperature (T g ) due to incorporating fibers was higher in the case of a PEF-reinforced composite than that of a GF-reinforced composite at the same volume fraction of fibers. It was also observed that the efficiency of both the composites decreases with the increase in the volume fraction of fibers.

Dynamic mechanical study on unidirectional polyethylene fibers‐PMMA and glass fibers‐PMMA composite laminates

Low concentrations of bromine (0.008–0.06M) were used to initiate photopolymerization of MMA in bulk and in diluted (near bulk) systems, the diluents or solvents used being benzene, toluene, dioxane, tetrahydrofuran, carbon tetrachloride, chloroform, methylene chloride, and methanol. Polymerization in bulk follows usual free-radical kinetics. Inert solvents (benzene, toluene) as well as the other solvents used enhance the rate of polymerization MMA even when used in the range of catalytic concentrations (0.04–0.4M). An initiation mechanism involving solvent molecules appears to be predominant in diluted systems.

Photopolymerization of methyl methacrylate with the use of iodine as the photoinitiator

Unidirectional (UD) hybrid composite laminates based on glass fibers (GF) and high performance polyethylene fibers (PEF) were prepared with partially polymerized methyl methacrylate (MMA) at room temperature, followed by heating at 55°C (well below the softening point of PEF) for 2 h. The total volume fraction of fibers of the hybrid composite was held constant and the proportion of PEF or GF was varied. The viscoelastic behavior of the hybrid composite was studied through dynamic mechanical analysis at different relative volume fractions of PEF. Parameters such as storage modulus (E''), and loss factor or damping efficiency (tan δ) were determined in a resonant frequency mode. All the properties were compared between the hybrid composites. It was found that the glass transition temperature (Tg) increased to a higher region with the increase in relative volume of PEF. It was also observed that the efficiency of the hybrid composite increased with the increase in relative volume of PEF. © 1996 John Wiley & Sons, Inc.

Amar Nath Banerjee

Papers

Dynamic mechanical study on unidirectional polyethylene fibers‐PMMA and glass fibers‐PMMA composite laminates

Photopolymerization of methyl methacrylate with the use of iodine as the photoinitiator

Dynamic mechanical study on unidirectional polyethylene–glass fibers: PMMA hybrid composite laminates

Flexural behavior of unidirectional polyethylene-carbon fibers-PMMA hybrid composite laminates

Tensile behaviour of unidirectional polyethylene-glass fibres/PMMA hybrid composite laminates