# Pune University Question Papers

B.E. (Polymer Engineering) POLYMER THERMODYNAMICS AND BLENDS (2008 Pattern)

(Elective – IV) (Sem. – II)

Time :3 Hours]                                                                           [Max. Marks :100

Instructions to the candidates:

1)            Answers to the two sections should be written in separate answer books.

2)           Draw neat diagrams wherever necessary.

3)           Numbers to the right indicate full marks.

4)           Assume suitable data, if necessary.

5)           Use of logarithmic table, electronic pocket calculator is allowed.

SECTION – I

QI) a) Explain the following terms :                                                               

i)                                 Heat

ii)           Internal Energy.

iii)                            Work.

b)         State The First Law Of Thermodynamics for Cyclic Process and derive the relation for the same for non flow process.                                                         

c)         State Limitations of The First Law Of Thermodynamics.                          

OR

Q2) a) Explain in detail Entropy term.                                        

b)        State The Third Law Of Thermodynamics.                                                   

c)        Explain the following terms :                                                                           

ii)           Equilibrium State.

iii)         Phase Rule.

iv)         Intensive Properties.

Q3) a) Explain in detail the necessity conditions governed by Free energy of mixing for Equilibrium – Phase Behaviour of mixtures.                                                 

b) Write a short note on effect of molecular weight on phase equilibrium. 

OR

Q4) a) Define the excess properties and derive the relation for SE, GE, HE, VE (S=Entropy, G=Gibbs free energy, H=enthalpy, V=volume and suffix E for excess)                   

b) Explain stable, metastable and unstable phases. State the thermodynamic conditions for Phase separations.                                                                                              

Q5) a) Plot a single graph, the composition dependence of the free energy of mixing per site (normalized by the thermal energy) AGmjx / kT of a symmetric polymer blend with NA=NB=100 using 5 different choices of parameter X=0.0.01, 0.02, 0.03, 0.04. Which choice of X make blends miscible in all proportions (i.e. over whole composition range 0 < 9 < 1)

and why? [ AYmjx = free energy of mixing, &=Boltzman constant, T=temperature, X= Flory interaction parameter, 9 =volume fraction]. 

b) Derive the ‘Flory Huggins equation for polymer blends’.                              

OR

Q6) a) Explain with one example.                                             

i)             Effect of Hydrogen bonding interaction.

ii)           Effect of Hilderbrand solubility parameter.

b) Explain with example from lattice theory why polymer blends have stymied entropy?                                                                                                                         

SECTION – II

Q7) a) Explain any two methods of preparation of Polymer Blends with suitable example.                                                                                                                               

b) With the help of two commercial examples, Property advantages and Applications discuss the term Miscible Blends.                                                           

OR

Q8) a) Discuss the advantages and disadvantages of the following engineering Polymeric modifier:                                                                                                              

i)             Polycarbonate (PC)

iii)        Polyethylene Terephthalate (PET).

b) Discuss the following terms with suitable examples :                                   

Ease of Processing, Economy, Enhanced Property, Ecology via Polymer Blend technology.

Q9) a) Discuss with examples Rubber Toughening of Brittle and Ductile Polymer matrix.        

b) Discuss the importance of Maleated Polymers in Polymer Blend Technology.  

OR

QI 0) a) Discuss Equilibrium Morphology and phase inversion concept in polymer blends.       

b) Discuss the role of compatibilizer and different factor contributing to end use properties of polymer blend.                                                                                       

QII) a) Explain the how to use known model system to predict rheology of miscible polymer blends.                                                                                                                   

b) Discuss the classifications of interpenetrating Polymer Network and discuss any one with suitable example.                                                                                        

OR

Q12) Write a note on :                                                                                     

a)         Semi-IPN of PU/PMMA.

b)        Compatibilized Blend of PS/PP.