Thermosets
• Phenol Formaldehyde
• Urea Formaldehyde
• Melamine Formaldehyde

Melamine Formaldehyde
• Good-to-excellent dimensional stability
• When used in the manufacture of closures, high torque strength and good impact strength.
• Good resistance to oils, grease, and many organic solvent

Phenol Formaldehyde
• Good scratch-resistant parts.
• Very low shrinkage and low water-absorption properties

Urea Formaldehyde
• Good dimensional stability as well as good strength properties
• Highly rigid and provide good resistance to alcohols,oils, grease, and some weak acids.
• Use for injection-molded heads for collapsible tubes used to contai liquid-based topical product.



Thermoplastics
Thermoplastics consist of those plastics that normally are rigid at operating temperatures but can be remelted and reprocessed.

Thermoplastics
• Polyethylene
• Polypropylene
• Polyethylene Terephthalate (PET)
• Polyvinyl chloride
• Polyvinylidene chloride
• Polystyrene
• Polycarbonate

Polyethylene (PE)
• Properties vary according to molecular weight and type.
   1. Low density polyethylene (LDPE) – branched chain
   2. High density polyethylene (HDPE) – linear chain
• Linear type is more crystalline, more heat resistant, and stiffer
• As crystallinity and density increase, opacity, stiffness, tensile strength, surface hardness, and chemical resistance increase.
• Both have low water absorption, high resistant to most solvents and chemicals and are tasteless and odorless.

High Density Polyethylene (HDPE)
• Is the most crystalline material (~ 95%)
• Naturally translucent
• HDPE has better moisture- barrier properties and better tensile strength than LDPE.
• HDPE is used widely for bottles of solid dosage form product.
• HDPE is NOT suitable for use with essential oils.

Low Density Polyethylene (LDPE)
• Has branched chains and limit crystallinity (60-65% crystallinity)
• More translucent than HDPE
• LDPE is used when flexibility is required, for squeeze bottles of spray and drops, as well as drum liner for bulk solid drugs.
• LDPE is significantly more expensive than HDPE

Polypropylene (PP)
• It has good resistance to cracking when flexed.
• Suitable for use in closures, tablet containers and intravenous bottles
• Lighter, much stiffer and more heat resistant than HDPE
• Same chemical resistance properties as HDPE
• Can be sterilized with steam and ethylene oxide,but not radiation, unless modified PP are used.
• Biaxial orientation PP (BOPP) will improve its clarity.
• Used wildly for solid dosage products.

Vinyl Plastics
• Vinyl group (CH2=CH-)
• Derivatives
   1. Vinyl chloride (CH2=CHCl)
   2. Vinylidene chloride (CH2=CCl2)
   3. Vinyl acetate (CH2=COCOCH3)
• Many polymers are made either as homopolymer of themselves or as copolymers with other vinyl derivatives or other monomer materials.

Polyvinyl chloride (PVC): Used as rigid packaging material and main component of intravenous bags.
• Unplasticised PVC : Bottle made PVC are naturally clear, have extremely good resistance to oils, and have very low oxygen transmission.
• Plasticised PVC : Plasticizer - DEHP (di(2-ethylhexyl)phthalate) is used most often. Plasticization also reduces chemical resistant and increases gas and moisture permeation

Polyvinyl chloride (PVC)
Factors to consider when PVC is uses for pharmaceutical
• Stablizers
• Plasticizer
• Monomer residue
• Modifiers
• Lubricants
• Catalylic residue

Polyvinylidene chloride (PVdC)
• Trade name “Saran”
• Copolymer of vinyl chloride or vinyl acetate and vinylidene chloride
• Excellent resistance to permeation by moisture and gas
• Most widely used as a coating

Polyethylene terephthalate (PET)
• USP : Polyethylene terephthalate (PET) and Polyethylene terephthalate (PETG) bottles that are interchangeably suitable for packaging liquid oral dosage form.
• PET resins are long-chain crystalline polymers prepared by the condensation of ethylene glycol with dimethyl terephthalate or terephthalic acid
• PET copolymer resins are prepared in similar way, except that they may contain a small amount of either isophthalic acid (NMT 3 mole percent) or 1,4-cyclohexanedimethanol (NMT 5 mole percent)
• PET copolymer resins have physical and spectral properties similar to PET

Polyethylene terephthalate (PET)
• PETG resin are high molecular weight polymers prepared by the condensation of ethylene glycol with dimethyl terephthalate or terephthalic acid and 15 to 34 mole percent of 1,4-cyclohexanedimethanol. PETG resins are clear, amorphous polymers.
• PET and PETG resins do not contain any plasticizers , processing aids, or antioxidants. Colorants,if used in the manuacture of PET and PETG bottles, do not migrate into the contained liquid.

Polystyrene (PS)
• PS has relative low heat resistance and is attacked by a number of chemical agents.
• Conventional grade – clear crystal grade, lack of impact strength.
• Impact-modified graded – copolymerized with acrylonitrile and butadiene, poor optical properties.
• It is also used for jars ointments and cream with low water content.

Polycarbonates
• PC are formed by condensation of polyphenols such as bisphenol-A with phosgene.
• PC are transparent thermoplastics with high strength and high temperatures resistance.
• Because they are expensive, their use is imited to specialty application.

Ionomer (Surlyn®)
• Are sodium or zinc salts of ethylene/ methacrylic acid copplymers.
• Is used as an inner ply in laminates, offering god heat sealing (even when the seal area is contaminated by liquid or powder) over a wide temperature range.
• Are clear , semiflexible, tough materials with good abrasion resistance.
• Valued in sachet and pouch packs.

Polymonochlorotrifluoroethylene (PCTFE)
“Aclar” film
• Has extremely low transmission of moisture.
• Transparent, and can be heat sealed, laminated, printed, thermoformed, metallized.
• Because it is the most expensive plastic used in the pharmaceutical industry, it is employed only where the most demanding barrier properties are required.
• Laminated Aclar/PVC sheet is used widely in thermoformed blister pack for moisture-sensitive solid dosage form.

Polyurethane Foams
• Are formed by polymerization in the presence of a foaming agent.
• Used as a replacement for cotton wool in tablet containers.

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