Plasticization, mechanical property

Substrate composition and phases Surface hardness and roughness at interface Grain size/microstructure Anisotropy in structure and properties Areal variation and batch-to-batch variation Elastic/plastic mechanical properties Fracture mechanics Flaw population and distribution Strain rate effects... 

Plasticizer Boiling % Plasticizer Mechanical properties % Weight loss... 

Sanadi, A.R., Caulfield, D.F., Jacobson, R.E., Rowell, R.M. Renewable agricultural fibers as reinforcing fillers in plastics mechanical properties of Kenaf fiber polypropylene composites. Ind. Eng. Chem. Res. 34, 1889-1896 (1995)... 

Densities range from 5 kg/m to the density of the soUd plastic. Mechanical properties are dependent on density and are nonUnear. 

Sanadi AR, Caulfield DF, Jacobsaon RE, Rowell RM (1995) Renewable agricultural fibres as reinforcing fillers in plastics mechanical properties of kenaf fibre-polypropylene composites. Ind Eng Chem Res 34 1889-18%... 

The radiation and temperature dependent mechanical properties of viscoelastic materials (modulus and loss) are of great interest throughout the plastics, polymer, and rubber from initial design to routine production. There are a number of laboratory research instruments are available to determine these properties. All these hardness tests conducted on polymeric materials involve the penetration of the sample under consideration by loaded spheres or other geometric shapes [1]. Most of these tests are to some extent arbitrary because the penetration of an indenter into viscoelastic material increases with time. For example, standard durometer test (the "Shore A") is widely used to measure the static "hardness" or resistance to indentation. However, it does not measure basic material properties, and its results depend on the specimen geometry (it is difficult to make available the identity of the initial position of the devices on cylinder or spherical surfaces while measuring) and test conditions, and some arbitrary time must be selected to compare different materials. 

Trimethylolethane trinitrate (metriol trinitrate) is not satisfactory as a plasticizer for nitrocellulose, and must be used with other plasticizers such as metriol triacetate. Mixtures with nitroglycerin tend to improve the mechanical properties of double-base cast propellants at high and low temperatures. Metriol trinitrate has also been used in combination with triethylene glycol dinitrate as a plasticizer for nitrocellulose. Its physical properties are Hsted in Table 7 (118-122). 

Mechanical properties are retained up to 200°C, even in continuous service, which is better than with most plastics. At high temperatures, these copolymers react with duorine, duorinating agents, and molten alkaU metals. They are commercially available under the Du Pont trademark Tedon FEP duorocarbon resin. A similar product is manufactured by Daikin Kogyo of Japan and sold under the trademark Neodon. The People s RepubHc of China also manufactures some FEP products. 

Density. Density is the most important variable in determining mechanical properties of a foamed plastic of given composition. Its effect has been recognized since foamed plastics were first made and has been extensively studied. 

The insulating value and mechanical properties of rigid plastic foams have led to the development of several novel methods of buUding constmction. Polyurethane foam panels may be used as unit stmctural components (220) and expanded polystyrene is employed as a concrete base in thin-sheU constmction (221). 

Table 13 is a representative Hst of nickel and cobalt-base eutectics for which mechanical properties data are available. In most eutectics the matrix phase is ductile and the reinforcement is britde or semibritde, but this is not invariably so. The strongest of the aHoys Hsted in Table 13 exhibit ultimate tensile strengths of 1300—1550 MPa. Appreciable ductiHty can be attained in many fibrous eutectics even when the fibers themselves are quite britde. However, some lamellar eutectics, notably y/y —5, reveal Htde plastic deformation prior to fracture. 

Mechanical Properties and Structural Performance. As a result of the manufacturing process, some cellular plastics have an elongated cell shape and thus exhibit anisotropy in mechanical, thermal, and expansion properties (35,36). Efforts are underway to develop manufacturing techniques that reduce such anisotropy and its effects. In general, higher strengths occur for the paraHel-to-rise direction than in the perpendicular-to-rise orientation. Properties of these materials show variabiUty due to specimen form and position in the bulk material and to uncertainty in the axes with respect to direction of foam rise. Expanded and molded bead products exhibit Httie anisotropy. 

Mechanical properties of plastics can be determined by short, single-point quaUty control tests and longer, generally multipoint or multiple condition procedures that relate to fundamental polymer properties. Single-point tests iaclude tensile, compressive, flexural, shear, and impact properties of plastics creep, heat aging, creep mpture, and environmental stress-crackiag tests usually result ia multipoint curves or tables for comparison of the original response to post-exposure response. 

Aromatic polyethers are best characterized by their thermal and chemical stabiUties and mechanical properties. The aromatic portion of the polyether contributes to the thermal stabiUty and mechanical properties, and the ether fiinctionahty faciUtates processing but stiU possesses both oxidative and thermal stabiUty. With these characteristic properties as well as the abiUty to be processed as mol ding materials, many of the aromatic polyethers can be classified as engineering thermoplastics (see Engineering PLASTICS). 

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