Solid Material Properties

Question 1

Stress Def

Answer 1

Applied force per unit area . During tableting this is typically pressure applied

Question 2

Strain Def

Answer 2

Deformation that occurs as a result of applied pressure. In tabletting this is crushing powder into smaller volume (plastic deformation)

Question 3

Fracture Def

Answer 3

Separation of a solid into 2 or more parts, occurs after high strain has occured

Question 4

Tablet progression as more strain is applied

Answer 4

elastic deformation -> plastic deformation -> brittle (/ductile) fracture

Question 5

Plastic deformation def

Answer 5

Permanent deformation after strain applied (past yield point). Molecules are pushed into slip planes where intermolecular forces are weaker. Ideal in tablets (volume reduction)

Question 6

Elastic Deformation Def

Answer 6

Temporary deformation after removal of applied stress. Reduction in intermolecular spacing

Question 7

Brittle Fracture Def

Answer 7

no apparent plastic deformation occurs before hand. Rapid propagation of a crack before shattering into pieces. Ideal in tablets

Question 8

Ductile fracture Def

Answer 8

Extensive plastic deformation. Materials are pulled apart uncommon for tablets

Question 9

Yield Point Def

Answer 9

Stress value where if it increased deformation would go from elastic to plastic

Question 10

Material Viscoelastic Behavior

Answer 10

Time dependent deformation that is either partially/fully reversible. Materials exprience to different extents dependent on their core materials

Question 11

Ductility Def

Answer 11

Ability of a material to undergo large plastic deformation without fracture

Question 12

Compression Def

Answer 12

Volume reduction when in confined space

Question 13

Compaction Def

Answer 13

Propensity of a powder to form a coherent tablet (evaluating bonds between particles). Material’s ability to exhibit tablet strength as a function of the solid fraction. Strong compacts are less prone to deformation (stronger bonds). Formed by plastic deformation and brittle fracture.

Question 14

Relationship between compaction propensity and density

Answer 14

Decreased propensity = decreased tablet volume = decreased tablet density

Question 15

Tensile Strength Def

Answer 15

Force from tablets internal bonds opposing compaction. Often measured by converting hardness test results

Question 16

Young’s Elastic Modulus Outline

Answer 16

Only valid for elastic deformation stage. Defines stiffness/toughness of a material. Higher Modulus = tougher material

Question 17

Heckel Plot

Answer 17

Describes compressibility by porosity (ln(1/(1-D))) (y-axis) vs pressure (x-axis). 1st order reaction

Question 18

Heckel Constant Outline

Answer 18

Slope of Heckel plot. 1/k = yield point

Question 19

Bonding Index Outline

Answer 19

Particle ability to form high tensile strength tablet

Question 20

Bonding Fracture Index Outline

Answer 20

Tablet ability to resist fracture when handling

Question 21

Compactibility Evaluates

Answer 21

Relationship between tensile strength and solid fraction

Question 22

Tabletability Evaluates

Answer 22

Relationship between tensile strength and compression pressure

Question 23

Compressibility evaluates

Answer 23

relationship between compaction pressure and solid fraction

Question 24

Compactibility, Tabilibility and Compressability indicate

Answer 24

Insight into manufacture process and properties of tablet. Assesment of deformation, yield and proposity