TGA measures the amount and the rate of change of the mass of a sample as a function of temperature/time in a system with controlled atmosphere. The data obtained from the graph may be used to identify a polymer and to study its properties like
a) Moisture content
b) Compositional analysis of Multi Component System
c) Estimation of product lifetime
d) Filler content of the material
e) Thermal stability
All these can be measured in an inert atmosphere like N2. Changing N2 by Air Oxidative degradation can also be studied which will be reported later.
Five unknown samples were sent to Lab for identification and study of their properties. TGA-DTA was carried out, the polymers were identified and the properties were studied.
The samples were characterized by using TGA.
Following experimental conditions were used:
|a) Instrument||Perkin Elmer STA 6000 (Pyris-6 TGA)|
|b) Sample mass||18-20mg|
|c) Heating rate||10OC/min|
|d) Temperature Range||30OC – 600OC|
|e) Sample pan||Ceramic pan with cover|
|f) Purge gas||Nitrogen|
TGA-DTA Tharmograms, Explanation of the Graphs for each of the five samples:
Interference and Identification of the Polymers:
Please find the five different TGA curve for these unknown polymers and the data obtained from the graph
|SAMPLE||MELTING POINT||MOISTURE CONTENT||DECOMPOSITION TEPERATURE(START)||DECOMPOSITION TEMPERATURE (COMPLETE)|
|A||137.5 OC||2.20%||1ST POLYMER 200OC 2ND POLYMER 380 OC||1ST POLYMER 380 OC 2ND POLYMER 485 OC|
|B||137.5 OC||0.75%||1ST POLYMER 200 OC 2ND POLYMER 400 OC||1ST POLYMER 400 OC 2ND POLYMER 500 OC|
|C||135 OC||0.55%||ONLY ONE 230 OC||ONLY ONE 500 OC|
|D||165 OC||0.54%||ONLY ONE 280 OC||ONLY ONE 500 OC|
|E||165 OC||0.27%||ONLY ONE 230 OC||ONLY ONE 480 OC|
A and B are composite C is a single polymer.
|Sample||Melting point||Name of the polymer||Composition||Filler||Moisture|
|A||137.5 OC||HDPE||1st Polymer 17.51% 2nd Polymer 72.30%||3.46%||2.20%|
|B||137.5 OC||HDPE||1st Polymer 14.54% 2nd Polymer 78.54%||3.44%||0.75%|
|C||135 OC||HDPE||Only one polymer 96.55%||2.30%||0.55%|
|D||165 OC||PP||Only one polymer 96.37%||0.92%||0.54%|
|E||165 OC||PP||Only one polymer 98.18%||0.93%||0.27%|
Sample A is made up of two HDPE polymers of two different degree of polymerization. The first one is 17.51% and the second one is 72.30%. Moisture content in this polymer is 2.20% and the filler material is 3.46%.
Sample B is made up of two HDPE polymers of two different degree of polymerization. The first one is 14.54% and second one is 78.54%.Moisture content is 0.75% and the filler material is 3.44%.
Sample C is made up of only one HDPE polymer. Polymer presents 96.55%. Moisture content is 0.55% and the filler material is 2.30%.
Sample D and E, both are made up of only one PP polymer. The polymer present in each sample is 96.37% and 98.18% respectively. The moisture and filler materials are 0.54%, 0.27% and 0.92%, 0.93% respectively.