Hydrazide blowing agents

Hunter B A and Schoene D L (1952) Sulfonyl hydrazide blowing agents for rubber and plastics, Ind Eng Chem 44 119-122. 

A most widely used decomposable chemical blowing agent is azodicarbonamide. Its decomposition temperature and rate of evolution of gaseous components are greatly influenced by the stabilizers containing zinc. Lead and cadmium are considered moderate activators for, -oxybis benzenesulfonyl hydrazide (OBSH). OBSH can also be used as a blowing agent for PVC foams. 

Products with very low dielectric constant (about 1.45) can be obtained by the use of cellular polymers. Blowing agents such as 4,4 -oxybisbenzenesulphono-hydrazide and azocarbonamide are incorporated into the polymer. On extmsion the blowing agent decomposes with the evolution of gas and gives rise to a cellular extrudate. Cellular polyethylene is a useful dielectric in communication cables. 

Chemical blowing agents undergo decomposition at the vulcanisation temperature to form a gaseous species such as nitrogen or carbon dioxide, e.g., azo compounds, nitroso compounds, sulphonyl hydrazide compounds, ammonium carbonate, ammonium bicarbonate and sodium bicarbonate. 

Toluol or methylbenzene a hydrocarbon of the benzene series, used as a solvent for rubbers. p-Toluene Sulphonyl Hydrazide TSH, blowing agent. o-Tolyl Biguanidine OTBG, accelerator. 

Some bis (sulfonyl) hydrazides and azides are used as blowing agents in the plastics industry to obtain plastic foams. 

Porofor. [Bayer Miles] AzodicaibCMi amide, hydrazides, or other chemical blowing agents for prod, of plastic foams, rubber goods. 

Benzene-1,3-disulfohydrazide 1,3-Benzenedisulfohydrazide. See Benzene-1,3-disulfonyl hydrazide Benzene-1,3-disulfonyl hydrazide Synonyms Benzene-1,3-disulfohydrazide 1,3-Benzenedisulfohydrazide Empirical C6H10N4O4S2 Properties Solid m.w. 266.31 dec. 115 C Uses Blowing agent for rubber goods... 

Carbon tetrabromide p-Tolylsulfonyl hydrazine blowing agent, rubber articles for repeated use food-contact Azodicarbonamide blowing agent, rubber goods Benzene-1,3-disulfonyl hydrazide ... 

Another method of modifying AZ is to mix it with such other CBAs as those from the sulfonyl hydrazide group. These auxiliary blowing agents decompose at lower temperatures than AZ, broadening the decomposition range. 

Azodicarbonamide, sulfonyl hydrazides, sulfonyl semicarbazides, and dinitro-pentamethylene tetramine are examples of exothermic blowing agents. Sodium borohydride, sodium bicarbonate, and polycarbonic acid are examples of endothermic blowing agents. 

Examples of chemical blowing agents are azo compounds, N-nitroso-compounds, and sulphonyl hydrazides, which yield 10()-3()() cm of nitrogen per gram of compound at temperatures of 90-2 7 5°C. Azodicarbonamide is widely used, having a decomposition temperature of 230-235°C, which can be reduced to 155-200°C by means of metal compounds such as lead and zinc stabilizers. It can thus match the temperatures at which the melt viscosity of many polymers is suitable for foaming, and is used (typically) in calendered PVC and PVC plastisols and in structural foam forms of polyethylene, polypropylene, PVC, polystyrene, and ABS. 

Description A = p-toluene sulfonyl semicarbazide general injection moulding B = 2.2 -azobisisobutyronitrile low-temperature blowing agent for rigid PVC C = 4,4 -oxybis(benzene sulfonyl hydrazide) PVC. LDPE/EVA foams ... 

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