Three statistical methods of general validity are valuable for characterizing any polymer which results from chain polymerization of multifunctional branching monomers linked through bifunctional monomers

Parker, J. A.

Winkler, E. L.

English

NASA Technical Reports Server

July 1971	 Brief 71-10255 
NASA TECH BRIEF 
Ames Research Center 
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Statistical Characterization of Phenolic-Novolak Structures 
fl
Three statistical methods are applied sequentially 
to characterize the structure of a phenolic-novolak. 
The first evaluates the total number of phenolic 
nuclei and methylene moieties that compose the 
average prepolymer molecule. The second evaluates 
the fraction of the total phenolic nuclei that are 
joined to the main structure by a single bond 
and are therefore pendent. The number average 
molecular weight for the prepolymer is calculated 
from these data. The third method is used to 
characterize the structure of the cured phenolic-
novolak in terms of the ratio of equivalents of 
curing agent to equivalents of prepolymer for 
any extent of cure. The sol fraction and the fraction 
of pendent phenolic nuclei that remain after curing 
are expressed in the same terms. 
Two discernible, overlapping reactions occur 
when phenolic- novolaks are pyrolytically decomposed. 
The extents of these reactions are related to the 
structure of the prepolymer and the extent of the 
crosslinking reaction. Thus, the fraction of the 
phenolic-novolak that is involved in each of the 
two pyrolysis reactions can be expressed in terms
of the structure of the prepolymer and the extent 
of the curing reactions. Experimental pyrolysis 
is only needed to determine the kinetic parameters 
for the pyrolysis reactions. 
The statistical methods described appear to be of 
general validity, and may prove valuable for 
characterizing any polymer which results from 
chain polymerization of multifunctional branching 
monomers linked through bifunctional monomers. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: TSP71-10255 
Patent status: 
No patent action is contemplated by NASA. 
Source: E. L. Winkler and J. A. Parker

Ames Research Center

(ARC-10393) 
Category 04 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
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Statistical characterization of phenolic-novolak structures

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