Mechanical Properties and Thermal Stability

Region I proportional or elastic range Region II elastic-plastic range Region III plastic range. 

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Solution reactions between diacid chlorides and diols or diphenols are carried out in THF or CH2C12 at —10 to 30°C in die presence of tertiary amines such as triethylamine or pyridine, which play a role of both reaction catalyst and HC1 acceptor (Scheme 2.26). This synthetic mediod is also termed acceptor-catalytic polyesterification.295-297 High-temperature solution reactions have also been reported for a number of less soluble, generally semicrystalline, aromatic polyesters.6 They yield high-molar-mass polyesters exhibiting good mechanical properties and thermal stability. 

PLA/PCL-OMMT nano-composites were prepared effectively using fatty amides as clay modifier. The nano-composites shows increasing mechanical properties and thermal stability (Hoidy et al, 2010c). New biopolymer nano-composites were prepared by treatment of epoxidized soybean oil and palm oil, respectively plasticized PLA modified MMT with fatty nitrogen compounds. The XRD and TEM results confirmed the production of nanocomposites. The novelty of these studies is use of fatty nitrogen compoimds which reduces the dependence on petroleum-based surfactants (Al-Mulla et al., 2011 Al-Mulla et ah, 2011 Al- Mulla et ah, 2010c). 

By analogy with the works which dealt with cellulose micro crystal-reinforced nanocomposite materials, microcrystals of starch [95] or chitin [96, 97] were used as a reinforcing phase in a polymer matrix. Poly(styrene-co-butyl acrylate) [95,96], poly(e-caprolactone) [96], and natural rubber [97] were reinforced, and again the formation of aggregates or clustering of the fillers within the matrices was considered to account for the improvement in the mechanical properties and thermal stability of the respective composites processed from suspensions in water or suitable organic solvents. 

Apart from the tuning of the host-guest interactions, the elaboration of efficient optical devices also relies on the optimization of the matrix mechanical properties and thermal stability. This is clearly demonstrated in the development of hybrid materials for NLO, and especially second harmonic generation (SHG). These properties rely on their noncentrosymetric organization of organic chromophores in the condensed phase. Becanse incorporation in a silica... 

When the mesogen moiety is included into the main chain of the polymer, the obtained macromolecule contains inherently rigid units, which usually result in remarkable mechanical properties and thermal stability. Fibers made by these polymers compete with the best ceramic fibers and are far superior to metal fibers [83]. They therefore are ideal candidates as reinforcements for polymer-based composites. However, these materials often have a poor miscibility and adhesion to other polymeric substrates, limiting the range of their applications. This problem basically arises from weak intermolecular interactions either within the liquid-crystalline polymer itself or with the matrix of the composite. Strong ionic... 

Mannans have been combined with inorganic nanoparticles as well as with cellulose to form nanocomposites (Table 9.5). The effect of added nanoparticles e.g. on the mechanical properties and thermal stability of films was studied. 

Kim, H.S., Park, B.H., Choi, J.H., Yoon, J.S. Mechanical properties and thermal stability of poly(L-lactide)/calcium carbonate composites. J. Appl. Polym. Sci. 109, 3087-3092 (2008)... 

Wang, R., Wang, S. and Zhang, Y. (2009) Morphology, mechanical properties, and thermal stability of poly(L-lactic acid)/poly(butylene succinate-co-adipate)/ silicon dioxide composites. Journal of Applied Polymer Science, 113, 3630-3637. 

A. R. Boccaccini, R. Liebald, W. Beier and K. K. Chawla, Fabrication, Mechanical Properties and Thermal Stability of a Novel Glass Matrix Composite Material Reinforced by Short Qxycaibide Fibres, J. Mat. Sci. 37, 4379-4384 (2002). 

Choi and Chung [16] were the first to prepare phenolic resin/layered sihcate nanocomposites with intercalated or exfoliated nanostructures by melt interaction using linear novolac and examined their mechanical properties and thermal stability. Lee and Giannelis [10] reported a melt interaction method for phenolic resin/clay nanocomposites, too. Although PF resin is a widely used polymer, there are not many research reports on PF resin/montmorillonite nanocomposites, and most of the research investigations have concentrated on linear novolac resins. Up to now, only limited research studies on resole-type phenolic resin/layered silicate nanocomposites have been published [17-19] and there is still no report on the influence of nano-montmorillonite on phenolic resin as wood adhesive. Normally H-montmorillonite (HMMT) has been used as an acid catalyst for the preparation of novolac/layered silicate nanocomposites. Resole resins can be prepared by condensation reaction catalyzed by alkaline NaMMT, just as what HMMT has done for novolac resins. 

Semi-interpenetrating polymer network membranes based on sulfonated polyimide-siloxane and epoxy polymers have been prepared [61]. The membranes show desirable mechanical properties and thermal stabilities, with proton conductivities superior to those of Nation 117 at 80 °C. 

The effects of interactions between functional PO chains and clay platelets, generating "confined" polymer fractions, onto the final performances of nanocomposites with particular reference to mechanical properties and thermal stability have been discussed in literature with wide reviews on the topic (Alexandre et al. 2002, Gopakumar et al. 2002, Sinha Ray and Okamoto 2003, Preston et al. 2004, Szazdi et al. 2006, Tjong 2006, Ciardelli et al. 2008). On the contrary, in absence of functionalities onto the backbone of POs, even if a certain degree of exfoliation can be reached by shearing forces, the lack of specific polar interactions negatively affects the general mechanical properties (Mittal 2007). 

F-2016 is a brominated epoxy oligomer with around 50% bromine and a molecular weight of 1600 designed to ensure optimal properties in styrenic copolymers. Brominated epoxy oligomers offer a combination of high flame retardant efficiency, UV stability, good mechanical properties and thermal stability. They are non-blooming due to their physicochemical properties and polymeric... 

Shojaei, A, Faghihi, M. Physico-mechanical properties and thermal stability of thermoset nanocomposites based on styrene-butadiene rubber/phenolic resin blend. Mat. Sci. Eng. A. 527, 917-926 (2010)... 

In order to prepare PLA nanocomposites with highly dispersed cellulose nanocrystals and porous PLA-based scaffolds with enhanced mechanical properties and thermal stability, CNCs have been incorporated into PLA fibres by electrospinning method. Fibrous biocomposite mats consisting of PLA and CNCs have been electrospun from solvent or solvent mixtures such as l,l,l,3,3,3-hexafluoro-2-propanol (HFP), DMF/chloro-form and DMF/tetrahydrofuran (THF). The electrospun PLA/CNCs bionanocomposites have demonstrated rapid in vitro biodegradability and cytocompatible properties, and could be potentially suitable in tissue engineering. ... 

In the first stage of our study, three aromatic diamines were used as chain extenders a non-symmetrical chain extender, 2,4-toluene diamine (TDA) two symmetric aromatic diamines 4,4 -methylene dianiline (MDA) and 4,4 -diamino-dibenzyl (DAB). TDA was used in order to improve the mechanical properties and thermal stability. The materials were synthesized by a two steps polyaddition reaction as... 

It should come to the benefits for physical properties of PU brought from nanoclay after gaining the understanding of unique morphology of PUCLNs. Silicate sheets are featured as mechanically strong and thermally stable nanoscale block, and they can be used to enhance the mechanical properties and thermal stability of PU. Two-dimensional structures can make them play as barrier to improve the permeability of PU. Therefore, the topics in this section will mainly cover enhanced mechanical, thermal, and barrier properties of PUCLNs. 

Alcock B, Cabrera N O, Barkoula N M and Peijs T (2009) The effect of processing conditions on the mechanical properties and thermal stability of highly oriented PP tapes, Euro Polym 45 2878-2894. 

Chemical character and size of solid surface areas, their porous structure, mechanical properties and thermal stability play an essential role in adsorption and catalysis ... 

Natural rubber/cw-1,4-polybutadiene (NR/BR) blends (70/30 mass ratio) have been widely used in the tire industry. Many nanocomposites based on organo-montmorillonite (OMMT)/rubber blends have been investigated. However, relatively little attention had been paid to binary rubber hybrids/ montmorillonite nanocomposites, and according to Zheng Gu et ah, no studies existed dealing with OMMT/NR/BR nanocomposites. So, the authors described the preparation of OMMT/NR/BR nanocomposites by direct mechanical blending and determined the cure characteristics, static mechanical properties, dynamic mechanical properties, and thermal stability of the nanocomposites. OMMT/NR/BR nanocomposites had exactly the same onset decomposition temperature and lower thermal degradation rate as the NR/BR blends. 

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