Amorphous resins

Color/Transparency. Almost all amorphous engineering thermoplastics, except PC and some polyester carbonates, are inherently colored. Even polycarbonates have yellowness indexes (YI) (36) of 0.1 to 5.0. Colorless material is produced from these resins by compounding with complementary blue dyes which reduce transmission. Ha2e in amorphous resins is an indication of particulates. Ha2e reduces optical clarity and transmission. 

Polymers can exist in a number of states. They may be amorphous resins, rubbers or fluids or they can be crystalline structures. TTie molecular and the crystal structures can be monoaxially or biaxially oriented. Heterogeneous blends of polymers in different states of aggregation enable materials to be produced with combinations of properties not shown by single polymers. 

The products are amorphous resins whose rigidity and softening point depend on the aldehyde used. Poly(vinyl butyral), with the larger side chain, is softer than poly(vinyl formal). Since the reaction between the aldehyde and the hydroxyl groups occurs at random, some hydroxyl groups become isolated and are incapable of reaction. A poly(vinyl acetal) molecule will thus contain ... 

Strength Fibrous minerals Ductility gaining tensile strength. Carbon fibers are more expensive fibrous minerals are least expensive but only slightly reinforcing. Reinforcement makes brittle resins tougher and embrittles tough resins. Fibrous minerals are not commonly used in amorphous resins. 

Deflection Temperature (HDT) Fibrous minerals Ductility yield much greater increases in HDT than do amorphous resins. As with tensile strength, fibrous minerals increase HDT only slightly. Fillers do not increase HDT. 

Temperature minerals cost cost amorphous resins. As with... 

Amorphous phase, of polymers, 20 400 Amorphous polymers, 10 203 crystallization of, 19 844 Amorphous red selenium, 22 74 Amorphous regions, in fibers, 11 171 Amorphous resins, use in thermoforming, 19 555... 

Compared to amorphous resins such as ABS, polycarbonate and polystyrene, a semicrystalline resin like PBT will show much better solvent resistance, higher... 

When the vinyl acetate content rises, polarity increases, and crystallinity and hardness decrease. For a 40-50% vinyl acetate content, the copolymer is an amorphous resin that is easily crosslinkable. 

The heat capacity is the amount of energy required to increase the temperature of a unit mass of material. It is commonly measured using a differential scanning calorimeter (DSC). The heat capacity depends on the resin type, additives such as fillers and blowing agents, degree of crystallinity, and temperature. A temperature scan for the resin will reveal the Tg for amorphous resins and the peak melting temperature and heat of fusion for semicrystalline resins. The heat capacities for LDPE and PS resins are shown in Fig. 4.15. 

Flow surging can occur if the temperature of the screw becomes too high in the solids-conveying section. In general, the temperature of the screw in this section needs to be less than the Tg for amorphous resins or less than the melting temperature for semicrystalline resins. Small-diameter screws will typically operate at feed... 

This resin is soluble in the cold in alcohol, ether, benzol, turpentine, bisulphide of carbon, and ebloro form all these liquids, when evaporated, leave as residue the amorphous resin. Dilute acids, concentrated alkaline solutions, and ammonia, do not attack the yellow resin. Monohydra tod sulphuric and nitric acids act upon it rapidly, producing phenomena analogous to those exhibited with the other two principles. Hydrochloric acid, even in ite sate rated solution at 68°, a without action upon it. But the most remarkable character of this resin Is the power of forming, under the circumstances already indicator , those globose crystals covered with a white pellicle of anothor resin, and presenting In their complex form the appearance of opaline spherules. 

Constitution and Properties.—Quinin is one of the more powerful organic alkalies. It generally appears, whan pure, as an amorphous, resinous mass, of a dull whits color. Its formula is—CM Hw Na Ot -(- 6 aq. It may also be obtained in six-sided prismatic crystals, which ore a hydrate, containing six equivalents, or 10 5 per cent, of water, which are lost on fusion. 

Figure A. The distribution of optically distinct materials in the cut-back and straight-distilled refractory pitches are different. The strongly anisotropic materials (oil phase) (A) contrast with the fine solids (S) in an amorphous resin from the original pitch and with the material which is more isotropic (I). At 450°C. another distinct isotropic phase (H) exists in the straight-distilled pitch, Reflected light...

K[(CH3)3Pt]Pt(CN)4, is isolated from an aqueous solution of the nitrate by adding potassium platinocyanide. A slimy yellow precipitate is formed, insoluble in water and the usual organic solvents except acetone and alcohol. On evaporation from one of these solvents an amorphous resinous greenish-yellow compound is produced which, from determination of the platinum, appears to correspond to K2Pt(CN)4[(CH3)3Pt]2Pt(CN)4. 

This deficiency is overcome by application of a hard coat to the amorphous resins this substantially improves resistance to the solvents and chemicals such as NMP, IPA, acetone, methanol, THF, ethyl acetate, 98% sulfuric acid, glacial acetic acid, 30% hydrogen peroxide, and saturated bases such as sodium hydroxide [13]. With poly(ethylene terephthalate) and of poly(ethylene naphthalate) films a hard coat is not required for solvent resistance. 

Polyethylene occurs as a white, translucent, partially crystalline and partially amorphous resin. It is produced by the direct... 

The coalescence of polymers is driven by the work of surface tension, which counteracts the viscous dissipation associated with the molecular diffusion within the coalescing domain. This phenomenon is often referred to in the literature as polymer sintering. In the rotational molding process, coalescence occurs at temperatures above that of the material melting point when dealing with semicrystalline polymers, or above the glass transition temperature for amorphous resins. The first analytical model describing the coalescence process was proposed by Frenkel ... 

Yamaki, H. Matsuura, Y. Method for Injection-Molding of Amorphous Resin IP Patent. 1-245252 A, 1999. 

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