UPTU Previous Year Exam Papers
BE 6th Semester Structure Property
and Characterization 2006-07
Note : Attempt all questions.
1. Attempt any four of the following :
(a) Define macromolecule. Classify the polymers on the basis of their origin, line structure, tacticity and crystallinty with the help of suitable examples.
(b) Define molecular weight of polymers. Discuss the various types of average molecular weights of polymers.
(c) Give the different methods for measuring the number-average molecular weight of polymers. Also, give the limitations of each of the methods.
(d) Write down the merits and demerits of measuring the molecular weights based on colligative properties.
(e) Discuss the effect of crystallinity on polymer properties.
2. Attempt any four of the following :
(a) What do you understand by spherulites? Discuss the effect on polymer properties due to formation of spherulites in the polymer structure.
(b) Discuss the polymer crystallization keeping in view the presence of geometrical regularity and polarity in the structure of polymers.
(c) What do you understand by fractionation? Give different methods of fractionation. How can you verily that the batch fractionation is conducted in highly dilute solution?
(d) Draw and discuss the Folded – chain crystallites models for the polymers.
(e) Highlight some physical and thermal properties of PET and PC with special reference to their structure.
3. Attempt any two of the following :
(a) Describe the Light scattering method for the determination of molecular weight of polymers.
(b) Describe solution viscometric technique for the determination of viscosity average molecular weight of polymers.
(c) Describe Ultra centrifugation technique for the determination of weight average molecular weight of polymers.
4. Answer any two of the following :
(a) What do you understand by the terms polymer solubility and solubility parameter? Based on solubility, highlight the following systems :
(i) Crystalline polar polymers and polar solvents.
(ii) Amorphous polar polymers and polar solvents.
(b) Discuss the principle and instrumentation of differential scanning calorimetric (DSC) analysis. What are the various parameters measured by DSC? Discuss them.
(c) What do you understand by glass-transition temperature (T ) for polymers? Explain the various structural factors, with examples, which affect the T of polymers.
5 . Write short notes on any two of the following :
(a) Thermogravimetric analysis (TGA)
(b) Copolymerization and its affect on polymer properties
(c) X-ray analysis for the measurement of polymer crystallinity.