Melt mixing method

The copolymers of vinylidene chloride (VDC) and BMA have high flexibility. Their tensile strength and toughness can be further improved by including proper amounts of VDC and BMA homopolymers. The melt mixing method cannot be used because the melting point of PVDC is high (nearly 200°C) [31]. The inclusion of the homopolymers via the concentrated emulsion method can, however, be easily achieved. Three preparation procedures were employed to... 

Achillas et al. [55] have prepared, by the melt mixing method, and characterized PHB/organically modified clay nanocomposites. 

In solution mixing, in order to overcome the limitations of melt mixing method, both the polymer and the nanoparticles are dissolved or dispersed in solution. This method enables modification of the particle surface without drying, which reduces particle agglomeration. After dissolvation the nanoparticle/ polymer solution can be cast into a solid, or solvent evaporation or precipitation methods can be used for isolation of nanoparticle/polymer composite. Conventional techniques can be used for further processing [Lee. E. S, 2004]. 

To achieve more uniform nanotube dispersion in composites, Haggenmueller et al. [59] developed an alternative melt mixing method consisting of a combined solution-evaporation technique to prepare a thin SWNT-polymer film followed by repeated compression molding of the latter. The resulting product was reported to yield compositionally uniform films. Using a small batch mixer, adequately dispersed nanotube composites from polypropylene, poly(acrylonitrile-butadiene-styrene), polystyrene, and high impact polystyrene have been prepared [60]. 

In the melt mixing method, nanoclays are incorporated into the polymer in the molten state. This technique has considerable advantages over either the in situ intercalative polymerization or polymer solution intercalation techniques. Firstly, this method is environmentally benign due to the absence of organic solvents. Secondly, melt processing is compatible with current industrial processes, such as extrusion and injection moulding. The melt intercalation method allows the use of biopolymers that were not suitable for in situ polymerization. This has been the most widely used method in the literature for obtaining PLA/clay nanocomposites. " ... 

MWNTs have been used as dispersed CNTs and network CNTs as reinforcements of phenolic matrices. Composite phenolic-dispersed CNTs were fabricated through the melt mixing method, which may lead to the agglomeration of CNTs in the matrix and introduce defects in composites. The infiltration of the resin into the network CNT generated composites with better mechanical properties when compared to the dispersed CNTs because the CNTs in the network are longer and contain fewer agglomerates and defects (Tai et al, 2004). 

Wang L, Cui ED, Sunada H (2006) Preparation and evaluation of solid dispersions of nitrendipine prepared with fine silica particles using the melt-mixing method. Chem Pharm Bull 54(1) 37-43 Wang G, Otuonye AN, Blair EA, Denton K, Tao Z, Asefa T (2009) Functionalized mesoporous materials for adsorption and release of different drag molecules a comparative study. J Solid State Chem 182(7) 1649-1660... 

Yin et al. [68] investigated the critical resistivity, dispersivity, and percolation threshold of low-density polyethylene carbon black. Li et al. [69] investigated the electrical properties and crystallization behavior of four different kinds of carbon black-filled polypropylene composites, prepared by the melt mixing method. All showed typical characteristics of percolation, but noticeably different percolation thresholds. When using carbon black with a higher structure, smaller particle diameter, and larger surface area, the composite showed better electrical conductivity and a lower percolation threshold. 

Nanocomposites based on starch/PVOH/silicate clay are not widely studied (Dean and others 2008 Vasile and others 2008 Majdzadeh-Ardakani and Nazari 2010). Dean and others (2008) produced a series of thermoplastic starch/PVOH/montmoril-lonite (MMT) micro and nanocomposites which exhibit intercalated and exfoliated structures through extrusion processing. A small amormt of PVOH (up to 7 wt%) and MMT (up to 5 wt%) were used and the improvement of tensile strength (up to 67% increase) and tensile modulus (up to 85% increase) were reported. Vasile and others (2008) prepared starch/PVOH/MMT composites by the melt mixing method. They revealed the morphology and thermal behavior changes for the nanocomposites and reported a slight increase in thermal stability for starch. 

Melt mixing method 1 utilizes well established technologies and is therefore generally preferred to obtain rubber-modified thermoplastics of improved impact properties. As the two components are immiscible, the addition of a third component (compatibilizing agent) is frequently used to increase the adhesion between the elastomeric and the thermoplastic phases and to achieve finer dispersions of the rubbery particles in the thermoplastic matrix. 

Shih et al. [27] fabricated green composites with fiber recycled from disposable chopsticks and PLA matrix by melt-mixing method. Mechanical tests showed that the tensile strength of the composites markedly increased with the fiber content, reaching 115 MPa in the case of being reinforced with 40 phr fibers, which was about three times higher than the neat PLA. 

---