To predetermine the mechanical properties of rigid plastics as a function of plasticizer content and composition, a set of equations has been empirically derived. These relate strain rate, yield stress, temperature, and weight fraction of the plasticizer

Lohr, J. J.

Parker, J. A.

English

NASA Technical Reports Server

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July 1964	 Brief 64-10068 
NASA TECH BRIEF	
_& 
This NASA Tech Brief is issued by the Technology Utilization Division to acquaint 
industry with the technical content of an innovation derived from the space program. 
Mechanical Properties of Plastics Predetermined by Empirical Method 
The problem: To develop a method for predeter-
mining the mechanical properties of rigid plastics as a 
function of plasticizer content and composition. 
Knowledge of the functional dependence of such 
factors as environmental temperature and vacuum 
conditions, ultraviolet irradiation, and strain rate on 
plasticizer parameters of various plastics would enable 
designers to select the materials best suited to par-
ticular applications. 
The solution: A set of empirically derived equa-
tions that relate strain rate, yield stress, temperature, 
and weight fraction of plasticizer. 
How it's done: Experiments were performed with 
1/32-inch polymethylmethacrylate sheet stock. Equa-
tions were derived from plots of the dependent vs 
independent variables. These equations can be used to 
predict the yield stress of polymethylmethacrylate at 
strain rates that cannot be readily applied in tests or 
to design for specific yield stresses. The equations are 
applicable for yield stresses from 3,000 to 19,000 psi 
for any combinations of strain rate, temperature, and
plasticizer content (methylmethacrylate or dibutyl-
phthalate) within the range of temperatures from 
-25'C to 100°C and plasticizer weight ratios from 
0 to 0.20. 
Note: 
Further information concerning this innovation is 
described in a paper entitled "The Combined Effects 
of Ultraviolet Radiation and Vacuum on the Tensile 
Yield Properties of Polymethylmethacrylate" by 
Jerome J. Lohr and John A. Parker, presented at the 
New York meeting of the American Chemical Society, 
Division of Polymer Chemistry, September 1963. 
Inquiries may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B64-10068 
Patent status: NASA encourages commercial use 
of this innovation. No patent action is contemplated. 
Source: Jerome J. Lohr and John A. Parker 
(ARC-28) - 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern-
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19640000024 2020-03-11T17:06:36+00:00Z


Mechanical properties of plastics predetermined by empirical method

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