Additives of Polymer, Additives of plastic, Improve properties of Plastic, Types of Additives
Download as PPTX, PDF18 likes10,719 views
The document outlines the role and types of additives used in plastics, which are substances added to enhance properties, processing, and cost-effectiveness of resins. Key categories mentioned include fillers, heat stabilizers, UV stabilizers, colorants, antistatic agents, and flame retardants, each serving specific purposes such as improving mechanical strength, preventing degradation, and reducing electrostatic charges. The document also describes the working mechanisms and examples of various additives and their effects on plastic materials.
Additives of Polymer, Additives of plastic, Improve properties of Plastic, Types of Additives
- 1. ADDITIVES 1
- 2. INTRODUCTION Additives: Any Substance that is added generally in small concentration to resins in order to : • Alter their properties • Facilitate processing • Change the physical, chemical or electrical properties of end products. • Reduce the cost 2
- 3. WHY TO USE ADDITIVES IN PLASTICS ? • Improve processing conditions • Increase resin’s stability to oxidation • Obtain better impact resistance • Increase or decrease hardness • Control surface tension • Facilitate extrusion moulding • Control blocking • Reduce cost • Increase flame resistance. 3
- 4. TYPES OF ADDITIVES 4 • Fillers • Antioxidants • Nucleating agent • Heat stabilizers • Plasticizer • UV stabilizers • Slip & Anti Block Agent • Colorants • Processing aids • Impact modifiers • Antistatic • Flame/fire retardants • Cross-linking agents • Blowing agents • Lubricants
- 5. FILLER 5 • It is used to modify mechanical properties & to reduce the cost. EFFECT OF FILLER • The use of inert fillers can influence the polymer properties in the following ways : • Increase in density. • Increase in modulus of elasticity. • Lower shrinkage. • Increase in hardness. • Increase in HDT. • Reduction of raw material cost. • For e.g. Calcium Carbonate
- 6. CLASSIFICATION OF FILLER • Mineral fillers : e.g. CaCO3 , kaolin, feldspar, talc etc. • Metallic, conductive & magnetic fillers : iron, copper, zinc & lead zinc & lead • Fire retarding fillers : Sb2O3 • Organic and special purpose fillers : carbon black, wood, flour, walnut flour. • Flake reinforcement : mica Flake reinforcement : mica • Continuous filament reinforcement : fibre glass, carbon graphite filaments etc. • Short fibre reinforcement : asbestos 6
- 7. HEAT STABILIZERS • To prevent degradation that occur during high temp processing/fabrication. • Prevent Degradation • Absorb & Neutralize HCl gas evolved • Prevent Oxidation reactions • Prevent Discoloration • Displace active substituents with stable substituents 7
- 8. HEAT STABILIZER • Lead • Tri Basic Lead Sulphate (TBLS) • Dibasic Lead Sulphate (DBLS) • Basic Lead Carbonate • Dibasic Lead Phosphate • Organo-tin • Dibutyltin maleates • Dibutyltin bis mercaptides • Cadmium / Barium /Zinc • Cadmium/Barium laurates • Cadmium/Barium/Zinc Complexes 8
- 9. UV STABILIZERS • UV stabilizers in plastics usually act by absorbing the UV radiation preferentially, and dissipating the energy as low-level heat. • Eg, Benzophenones – for PE, Polyesters Benzotriazoles – for PS, Polyesters Carbon black 9
- 10. COLORANTS • Produces varieties of colored polymers • Also improves – Mechanical Strength – Specific Gravity – Clarity • Types Of Colorants • Dyes (soluble in polymers) • Pigments (insoluble) 10
- 11. COLORANTS • Dyes : • Impart brilliant transparent color to clear plastics • Inorganic & Organic • AZOS for brightness and clarity • Anthraquinone (AQ) –Good heat transparent weathearibility (Auto tube light) • Pigments : • Diarylide pigment • Lead chromate 11
- 12. ANTISTATIC AGENT • Prevent electrostatic charges – mostly seen in PE, PP, PS, Nylons, Polyesters, Urathenes, Cellulosics, Acrylics & Acrylonitriles • Because of insulation properties electrical charge may get deposited on the surface of the plastics produced during processing. • This may cause severe damage to the products & equipments. • It may cause accumulation of dust. • The accumulation of static charge can be minimized by the use of antistatic agents. • Chemicals added to plastics to reduce built up of electrostatic charges on the surface of materials 12
- 13. ANTISTATIC AGENT • Eg, • Amines • Quaternary ammonium compounds, • Phosphates • Polyethylene glycol esters 13
- 14. FIRE RETARDANTS • Polymers being organic compounds burn or decompose on exposure to fire, generates toxic fumes, smoke. • Eg, • Inorganic : Zinc borate • Halogenated : Chlorinate paraffins • Applicable to polymers to be used in mines, automobiles, air vehicles, railways, etc. 14
- 15. CROSS LINKING AGENT • Thermosets cure either on application of heat or cross linking/curing/ hardening agents. • In some cases agent triggers off the reaction & therefore linking the resin molecules or It enters into the parts between molecules and completes the chain. • Classification : • free radical initiator : Isobutyl nitrile, Alkyl peroxide . • non free radical agents : Isocyanate with polyol • Used : Manufacture of Thermosets like polyurethane, Urea Formaldehyde, etc. 15
- 16. BLOWING AGENT • Polymeric foams preparation • Mechanical • Chemically • Substances called blowing agents, which on heating decompose giving N & CO2. • Applications: mattresses, pillows, insulation, foam pipes for non-p conditions. e.g. Para toluene sulphonyl hydrazide. 16
- 17. LUBRICANTS • Hot processing of polymers need lubricants either internally or externally. • Internal lubricants decreasing normal cohesive forces between polymer molecules good flow conditions by lowering viscosity. • They function by reducing intra-molecular friction before and during the melt formation of the polymer by promoting flow and reducing melt viscosity of the polymeric mass. • They also enhance polymer properties like heat stability, impact strength, colour & clarity. • Eg, Amine Waxes ,Ester Derivatives . 17
- 18. LUBRICANTS • External lubricant don’t let melt to stick to hot surface of processing. By forming a thin layer at melt-solid interface. • Prevent friction between polymer melt & metal surface • Prevent sticking to the metal parts • They are usually high molecular compounds and have non-polar groups. • Eg, Metal Stearates, Zinc Stearates, Calcium Stearates, Magnesium Stearates, Hydrocarbon waxes 18
- 19. IMPACT MODIFIERS • To enhance the impact properties of certain brittle polymers so as to use in the field. • E.g. • Chlorinated polyethylene EVA are used for PVC. • SBR is used for polystyrene material. • EPDM is used for PP ( Bumpers) • Acrylic rubbers for Poyamides 19
- 20. ANTIOXIDANTS • They inhibit or retard the oxidative degradation of materials at normal or elevated temperature during processing, storage or service due to • Heat • Light • Chemical Induction • How it works? – It interrupt the chain reaction by combining with the free radicals forming a non reactive products • E.g, Hindered Phenols or Aromatic Amines 20
- 21. PLASTICIZERS • Improve process ability by reducing Tg • These are high boiling non-volatile solvents. • Polar with a high Mol. Wt. ester type organic compounds. • Reduce internal friction between polymer chain. • Effect of plasticizer • Easy melt • Improve flexibility • Increase Softness and Flexibility. • Improve Process ability. 21
- 22. PLASTICIZERS • Primary Plasticizers – These are highly compatible with PVC and can be used alone. • Eg, Phthalates, Di-Octyl Phthalate (DOP), Di Iso Octyl Phthalate (DIOP) Phosphates, Tricresyl Phosphate (TCP). • Secondary Plasticizers – These are less compatible with resin & and are usually employed together with primary plasticizers. • Eg, Di Octyl Sebacate (DOS), Adipic Acid Polyesters, Epoxidised oil. 22
- 23. SLIP & ANTI BLOCK AGENT • Slip : Reduces coefficient of friction- They are high molecular weight fatty alcohols. • Amount (0.05 – 0.2% ) e.g. For film of 25 micron 0.01% of Oleamide. • Anti block Agents : Prevent adhesion between the film surface Amount (0.05 -0.2%). • E.g. – Calcium Carbonate in PVC film – Metal Salts – Fatty Acids – Natural & Synthetic Waxy Materials. 23
- 24. NUCLEATING AGENT • Aiding transmission of white light in Plastics • Forms large nos. of nuclei & reduces the size of spherulites. • Eg. – Sodium, Potassium, Lithium benzoates. – Inorganic Powders – Clays, Silica Flour. 24
- 25. THANK YOU 25