Polymers

Question 1

what is a polymer?

Answer 1

polymers are a specific type of macromolecule- molecules that are composed of a large number of atoms with a high molecular weight
polymers are built up of repeating units called monomers

Question 2

what are the different ways a polymer can be arranged?

Answer 2

homopolymer
alternating copolymer
random copolymer
block polymer
graft polymer

Question 3

what do the properties of polymers depend on?

Answer 3

property of the monomer itself
arrangment of the monomers
how the polymer chains interact with eachother and/or the environment

Question 4

what can block polymers act as?

Answer 4

suspending agents

Question 5

what is the dissolution of polymers dependant on?

Answer 5

polar/ non-polar
molecular weight
presence of crosslinking
crystalline or amorphous form

Question 6

what is polydisperse?

Answer 6

polymers do not have an exact molecular weight

Question 7

if polymers are sufficently polar they are also…?

Answer 7

likely to dissolve in water

Question 8

water-soluble polymers are potentially able to…?

Answer 8

increase the viscosity of solvents
swell/change shape
adsorb at surfaces

Question 9

insoluble polymers…

Answer 9

are often capable of forming thin films and are used in tablet coating, wound dressing, membranes…

Question 10

what are the layers present at polymer dissolution?

Answer 10

diffusion layer
gel layer
infiltration layer

Question 11

what are the characteristics of polymer dissolution?

Answer 11

slow polymer dissolution rates
existence of these layers creates opportunities for developing modified release dosage forms

Question 12

the more crystalline a polymer is then the ____ the dissolution rate?

Answer 12

lower

Question 13

what is rheology?

Answer 13

study of flow and deformation of matter

Question 14

what is viscosity?

Answer 14

the resistance to flow

Question 15

what is shear?

Answer 15

the relative motion between adjacent layers of a moving fluid

Question 16

fluids that show shear are called what?

Answer 16

newtonian fluids

Question 17

what is shear rate?

Answer 17

the velocity gradient over the heigh in our block of fluid

Question 18

what is shear stress?

Answer 18

the force applied over the area of the upper surface of the block

Question 19

what is the viscosity equation?

Answer 19

applied shear stress= viscosity x shear rate

Question 20

what are the charecteristics for non-newtonian fluids?

Answer 20

fluid often decrease in viscosity with increasing shear rate
some fluids increase in viscosity with increasing shear rate

Question 21

what is shear thinning also known as?

Answer 21

pseudoplastic flow

Question 22

how does viscosity and polymer concentration relate?

Answer 22

viscosity increases with polymer concentration

Question 23

low concentration of polymers?

Answer 23

isolated polymer chains, shape and volume determined by polymer-solvent and intra-polymer interactions

Question 24

high concentration of polymers?

Answer 24

inter-penetrating chains
polymer movement hindered by neighbouring chains
inter and intra polymer interactions

Question 25

what is a capillary viscometer used for?

Answer 25

determining the viscosity of newtonian fluids

Question 26

what is a roating viscometer used for?

Answer 26

determining the viscosity of newtonian and nonnewtonian liquids

Question 27

what are the key materials used in pharmaceutucal packaging?

Answer 27

glass, metal, plastics and paper

Question 28

what factors are increasingly being considered by the pharmaceutical industry regarding packaging?

Answer 28

sustainability and environmental factors