Thermal properties crystallization

H. Tsuji, Y. Kawashima, H. Takikawa, S. Tanaka, Poly(L-lactide)/nano-structured carbon composites Conductivity, thermal properties, crystallization, and biodegradation., Polymer, vol. 48, pp. 4213-4225, 2007. 

The effects of nano-structured carbon fillers [fuUerene C60, single wall carbon nanotube (SWCNT), carbon nanohom (CNH), carbon nanoballoon (CNB), and ketjenblack (KB) and conventional carbon fillers [conductive grade and graphi-tized carbon black (CB)]] on conductivity (resistance), thermal properties, crystallization, and proteinase K-catalyzed enzymatic degradation of PLA films were investigated by Tsuji et al. [70]. The researchers found that the addition of 1 wt% SWCNT effectively decreased the resistivity of PLA film compared with that of conventional CB. The crystallization of PLA further decreased the resistivity of films. The addition of carbon fillers, except for C60 and CNB at 5 wt%, lowered the glass transition temperature, whereas the addition of carbon fillers, excluding... 

Thermal Properties Crystallization and Glass-Transition Behavior... 

Funasako, Y, Inagaki, T., Mochida, T., Sakurai, T., Ohta, H., Furukawa, K. and Nakamura, T., Organometallic ionic liquids from alkyloctamethylferrocenium cations Thermal properties, crystal structures, and magnetic properties, Dalton Trans. 42, 8317-8327 (2013). 

The many commercially attractive properties of acetal resins are due in large part to the inherent high crystallinity of the base polymers. Values reported for percentage crystallinity (x ray, density) range from 60 to 77%. The lower values are typical of copolymer. Poly oxymethylene most commonly crystallizes in a hexagonal unit cell (9) with the polymer chains in a 9/5 helix (10,11). An orthorhombic unit cell has also been reported (9). The oxyethylene units in copolymers of trioxane and ethylene oxide can be incorporated in the crystal lattice (12). The nominal value of the melting point of homopolymer is 175°C, that of the copolymer is 165°C. Other thermal properties, which depend substantially on the crystallization or melting of the polymer, are Hsted in Table 1. See also reference 13. 

Mechanical and Thermal Properties. The first member of the acrylate series, poly(methyl acrylate), has fltde or no tack at room temperature it is a tough, mbbery, and moderately hard polymer. Poly(ethyl acrylate) is more mbberflke, considerably softer, and more extensible. Poly(butyl acrylate) is softer stiU, and much tackier. This information is quantitatively summarized in Table 2 (41). In the alkyl acrylate series, the softness increases through n-octy acrylate. As the chain length is increased beyond n-octy side-chain crystallization occurs and the materials become brittle (42) poly( -hexadecyl acrylate) is hard and waxlike at room temperature but is soft and tacky above its softening point. 

Solubility Properties. Fats and oils are characterized by virtually complete lack of miscibility with water. However, they are miscible in all proportions with many nonpolar organic solvents. Tme solubiHty depends on the thermal properties of the solute and solvent and the relative attractive forces between like and unlike molecules. Ideal solubiHties can be calculated from thermal properties. Most real solutions of fats and oils in organic solvents show positive deviation from ideaHty, particularly at higher concentrations. Determination of solubiHties of components of fat and oil mixtures is critical when designing separations of mixtures by fractional crystallization. 

Density, mechanical, and thermal properties are significantly affected by the degree of crystallinity. These properties can be used to experimentally estimate the percent crystallinity, although no measure is completely adequate (48). The crystalline density of PET can be calculated theoretically from the crystalline stmcture to be 1.455 g/cm. The density of amorphous PET is estimated to be 1.33 g/cm as determined experimentally using rapidly quenched polymer. Assuming the fiber is composed of only perfect crystals or amorphous material, the percent crystallinity can be estimated and correlated to other properties. 

For cubic crystals, which iaclude sUicon, properties described by other than a zero- or a second-rank tensor are anisotropic (17). Thus, ia principle, whether or not a particular property is anisotropic can be predicted. There are some properties, however, for which the tensor rank is not known. In addition, ia very thin crystal sections, the crystal may have two-dimensional characteristics and exhibit a different symmetry from the bulk, three-dimensional crystal (18). Table 4 is a listing of various isotropic and anisotropic sUicon properties. Table 5 gives values for the more common physical properties and for some of the thermodynamic properties. Figure 5 shows some thermal properties. 

A very high, price and performance family of polymers called liquid crystal polymers (LCPs) exhibit extremely high mechanical and thermal properties. As their ease of processing and price improve, they may find appHcation in thin-waH, high strength parts such as nails, bolts, and fasteners where metal parts cannot be used for reasons of conductivity, electromagnetic characteristics, or corrosion. 

Thermal properties and decomposition mechanisms depend on the crystal structure type. Compounds with a crystal structure that includes shared octahedrons decompose forming tantalum- or niobium-containing gaseous components, while island-type compounds release light atoms and molecules into the gaseous phase. 

Their special field of investigation dealt with the electrical and thermal properties of metals. More recently considerable attention has been paid to the question of the nature of the interatomic forces in metals, which are significant for properties such as density, compressibility, crystal energy, and hardness and it has been found possible to treat this problem in a reasonably satisfactory way for the case of the alkali metals, with a single valence electron per atom.8... 

Continuing their efforts with similar ligands, they prepared a thermally sensitive crystal of a bis(/i-qxo)dicopper(II I) compound (3).28 Average Cu O bond distance and Cu-Cu distance are 1.806 A and 2.743 A, respectively. Spectroscopic and kinetic parameters for this compound were also investigated. They also studied the reactivity properties of the copper-dioxygen complexes.25... 

Since excellent reviews on block copolymer crystallization have been published recently [43,44], we have concentrated in this paper on aspects that have not been previously considered in these references. In particular, previous reviews have focused mostly on AB diblock copolymers with one crystal-lizable block, and particular emphasis has been placed in the phase behavior, crystal structure, morphology and chain orientation within MD structures. In this review, we will concentrate on aspects such as thermal properties and their relationship to the block copolymer morphology. Furthermore, the nucleation, crystallization and morphology of more complex materials like double-crystalline AB diblock copolymers and ABC triblock copolymers with one or two crystallizable blocks will be considered in detail. 

There are several comprehensive textbooks and review articles devoted to organic superconductors [3,4,182-186] which describe design and preparation, crystal and band structures, chemical, transport, magnetic, optical, and thermal properties, and theory. 

A variety of surface-sensitive spectroscopic and microscopic methods were critical in the investigation of these systems. In the work by Advincula et al, the composition, thickness, physical and thermal properties, and morphology of the tethered polymer brushes were carefully analyzed [72]. A variety of surface-sensitive techniques such as ellipsometry, contact angle measurements, AFM, quartz crystal microbalance (QCM), FT-IR grazing incidence... 

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