Nucleation agent

A low incidence of explosions has been reported when precipitation is effected without a nucleating agent and during the screening process. Precautions must be taken during detonator loading to prevent dusting and to maintain a scmpulously clean operation. 

Cellulose Acetate. The extmsion process has also been used to produce ceUular ceUulose acetate (96) ia the deasity range of 96—112 kg/m (6—7 lbs /fT). A hot mixture of polymer, blowiag ageat, and nucleating agent is forced through an orifice iato the atmosphere. It expands, cools, and is carried away on a moving belt. 

The development of the principles of nucleation and growth eady in the twentieth century (2) ultimately led to the discovery that certain nucleating agents can induce a glass to crystallize with a fine-grained, highly uniform microstmcture that offers unique physical properties (3). The first commercial glass-ceramic products were missile nose cones and cookware. 

Polyethylene. This is essentially a closed-ceU insulation manufactured at 448 2 K by an extmsion process. A blowing agent and nucleating agent are employed to control the ceU size, and primary use is in insulating pipelines for hot and chilled water lines, air conditioning, and processing systems. 

Polypropylene molecules repeatedly fold upon themselves to form lamellae, the sizes of which ate a function of the crystallisa tion conditions. Higher degrees of order are obtained upon formation of crystalline aggregates, or spheruHtes. The presence of a central crystallisation nucleus from which the lamellae radiate is clearly evident in these stmctures. Observations using cross-polarized light illustrates the characteristic Maltese cross model (Fig. 2b). The optical and mechanical properties ate a function of the size and number of spheruHtes and can be modified by nucleating agents. Crystallinity can also be inferred from thermal analysis (28) and density measurements (29). 

The relative effectiveness of nucleating agents in a polymer can be determined by measuring recrystallization exotherms of samples molded at different temperatures (105). The effect of catalyst concentration and filler content has been determined on unsaturated polyesters by using dynamic thermal techniques (124). Effects of formulation change on the heat of mbber vulcanization can be determined by dsc pressurized cells may be needed to reduce volatilization during the cure process (125). 

PET does not crystallise well in the unoriented state even in a hot mold unless nucleating agents and/or plasticisers are added. Commercial PET ... 

The consumption of 4-/ f2 -butylphenol in the production of phenohc resins represents an appHcation in a mature market and Htfle growth is projected. Its use in end-capping polycarbonates, in the production of glycidyl ethers, and in the production of nucleation agents for polypropylene is expected to grow at a rate above the growth of the GNP (see Table 3). 

The solvent-free mono- -butyl, monoisopropyl bis-acetylacetone titanate, TYZOR AA95 [9728-09-9] is a Hquid at room temperature. By carefully controlling the mixture of alcohols used as solvent, a product, TYZOR GBA can be obtained, which is cold-storage-stable even in the presence of nucleating agents (96). 

Barium bromide is very soluble in methanol, yet almost insoluble in ethanol. Repotted uses of barium bromide include fabrication of phosphors, for example from Bap2, BaBi2 2H O and EuBy (6) as a crystallization nucleating agent to control supercooling of CaBi2 solutions (7) and in the production... 

Benzothiazolin-3-ylacetic acid, 4-chloro-2-oxo-as herbicide, 6, 328 as plant growth regulator, 1, 191 Benzothiazolium bromide, 2-methyl-3-propargyl-nucleating agent... 

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