Chemical Resistance of Materials for Tubes and Hoses

B = Limited suitability, e.g., only for empty hose systems or short-time operation C = Not suitable, material degrades after short time of exposure H = Conflicting data available. Suitability must be tested 

Medium Temp. [°C] 1 Chemical resistance of inner layers  

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Table A.42 Chemical resistance of materials for tubes and hoses, Temp. = temperature...

The connections for fluid contact have the task of ensuring ingress of the starting materials to the microreactor and egress of the products. They are normally miniature hoses made of PTFE or pipes made of chemically resistant stainless steel. Common diameters are 1 /8 and 1 /16 in fittings with 1/4 in UNF thread are employed for PTFE hoses and the steel tubing is fixed with jubilee dips. A variety of methods are used to fix compatible connection points on the microreactor. Here three of them will be described. 

PVOH (or tradename PVAL) is a crystalline, white powder soluble in water and alcohols. It is characterized by water solubility, low gas permeability barrier, high resistance to organic solvents other than alcohol, and crystallinity when stretch oriented. Crystallinity allows the material to polarize light. A series of hydrolysis levels of the plastic are available that range from room temperature solubility to those not soluble at all. The major applications of the PVOHs are in elastomeric products, adhesives, films, and finishes. Extruded PVOH hoses and tubing are excellent for use subjected to contact with oils and other chemicals. PVOH is used as a sizing in the manufacture of nylon. 

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