Method for employing SEC-FTIR data to predict mechanical properties of polyethylene
AssigneeChevron Phillips Chemical Company LP
InventorsPaul J. DesLauriers, David C. Rohlfing
Life of this patent
Estimating the term…
Abstract
The present invention provides several methods of determining values of physical or chemical properties of polymers. In these methods, at least two polymer training samples are provided. Characteristics of the polymer microstructures of the training samples are correlated with values of physical or chemical properties of the training samples. These correlations are subsequently applied to the respective characteristics of polymer test samples in order to determine the values of physical or chemical properties of the test samples.
Claims37
A method of determining a value of a physical or chemical property of at least one polymer test sample, the at least one polymer test sample having a molecular weight distribution (MWD) profile and a short chain branching distribution (SCBD), comprising:
- a) providing at least two polymer training samples, each training sample having a MWD profile, a SCBD, and a known value of the respective physical or chemical property;
- b) determining at least two weighted cross terms at respective molecular weights along the MWD profile and the SCBD, for each of the at least two polymer training samples and the at least one polymer test sample, each weighted cross term being determined as the multiplication product of:
- (1) the respective molecular weight;
- (2) the weight fraction at the respective molecular weight;
- and
- (3) the number of short chain branches per 1000 carbon atoms at the respective molecular weight;
- c) plotting each weighted cross term versus the logarithm of the respective molecular weight for each of the at least two polymer training samples and the at least one polymer test sample;
- d) determining the respective area under each curve in step c);
- e) correlating the respective areas for each of the at least two polymer training samples in step d) with the known value of the respective physical or chemical property;
- and
- f) applying the correlation of step e) to the respective area of the at least one polymer test sample to determine the value of the physical or chemical property of the at least one polymer test sample.
A method of determining a value of a physical or chemical property of at least one polymer test sample, the at least one polymer test sample having a MWD profile and a SCBD, comprising:
- a) providing at least two polymer training samples, each training sample having a MWD profile, a SCBD, and a known value of the respective physical or chemical property;
- b) determining at least two weighted cross terms at respective molecular weights along the MWD profile and the SCBD, for each of the at least two polymer training samples and the at least one polymer test sample, each weighted cross term being determined as the multiplication product of:
- (1) the respective molecular weight;
- (2) the weight fraction at the respective molecular weight;
- and
- (3) the number of short chain branches per 1000 carbon atoms at the respective molecular weight;
- c) by chemometric analysis, defining a mathematical relationship between the values of the respective physical or chemical property and the weighted cross terms for each of the at least two polymer training samples;
- and
- d) applying the mathematical relationship of step c) to the respective weighted cross terms of step b) for the at least one polymer test sample to determine the value of the physical or chemical property of the at least one polymer test sample.
A method of determining a value of a physical or chemical property of at least one polymer test sample, the at least one polymer test sample having a composite density, a MWD profile, and a SCBD, comprising:
- a) providing at least two polymer training samples, each training sample having a composite density, a MWD profile, a SCBD, and a known value of the respective physical or chemical property;
- b) determining at least two density terms at respective molecular weights along the MWD profile and the SCBD, for each of the at least two polymer training samples and the at least one polymer test sample, each density term being determined using the composite density, the MWD profile, and the SCBD;
- c) determining a respective melting temperature from each density term in step b);
- d) determining a respective probability for tie molecule formation from each melting temperature in step c);
- e) determining a respective weighted tie molecule probability, each weighted tie molecule probability being determined as the multiplication product of:
- (1) the weight fraction at the respective molecular weight;
- and
- (2) the probability for tie molecule formation in step d) at the respective molecular weight;
- f) plotting each weighted tie molecule probability versus the logarithm of the respective molecular weight for each of the at least two polymer training samples and the at least one polymer test sample;
- g) determining the respective area under each curve in step f);
- h) correlating the respective areas for each of the at least two polymer training samples in step g) with the known value of the respective physical or chemical property;
- and
- i) applying the correlation of step h) to the respective area of the at least one polymer test sample to determine the value of the physical or chemical property of the at least one polymer test sample.
A method of determining a value of a physical or chemical property of at least one polymer test sample, the at least one polymer test sample having a molecular weight, a weight fraction at the respective molecular weight, and a number of short chain branches per 1000 carton atoms at the respective molecular weight, comprising:
- a) providing at least two polymer training samples, each training sample having a molecular weight, a weight fraction at the respective molecular weight, a number of short chain branches per 1000 carton atoms at the respective molecular weight, and a known value of the respective physical or chemical property;
- b) determining a weighted cross term at the respective molecular weight for each of the at least two polymer training samples and the at least one polymer test sample, each weighted cross term being determined as the multiplication product of:
- (1) the respective molecular weight;
- (2) the weight fraction at the respective molecular weight;
- and
- (3) the number of short chain branches per 1000 carbon atoms at the respective molecular weight;
- c) correlating the respective weighted cross terms for each of the at least two polymer training samples in step b) with the known value of the respective physical or chemical property;
- and
- d) applying the correlation of step c) to the weighted cross term of the at least one polymer test sample to determine the value of the physical or chemical property of the at least one polymer test sample.
Dependencies are inferred from the claim text.