The document discusses the modification of polyethylene through chlorination and chlorosulphonation to produce chlorinated polyethylene (CPE) and chlorosulphonated polyethylene (CSM). It provides details on the chemical structure, properties, processing, applications and formulations of CPE and CSM.
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The document discusses the modification of polyethylene through chlorination and chlorosulphonation to produce chlorinated polyethylene (CPE) and chlorosulphonated polyethylene (CSM). It provides details on the chemical structure, properties, processing, applications and formulations of CPE and CSM.
Original Description:
an introductory presentation on CPE and CSM rubbers
The document discusses the modification of polyethylene through chlorination and chlorosulphonation to produce chlorinated polyethylene (CPE) and chlorosulphonated polyethylene (CSM). It provides details on the chemical structure, properties, processing, applications and formulations of CPE and CSM.
Copyright:
Attribution Non-Commercial (BY-NC)
Available Formats
Download as PPT, PDF, TXT or read online from Scribd
The document discusses the modification of polyethylene through chlorination and chlorosulphonation to produce chlorinated polyethylene (CPE) and chlorosulphonated polyethylene (CSM). It provides details on the chemical structure, properties, processing, applications and formulations of CPE and CSM.
Copyright:
Attribution Non-Commercial (BY-NC)
Available Formats
Download as PPT, PDF, TXT or read online from Scribd
Modification of Polyethylene Advantage of choosing PE: Saturated backbone Cheapest monomer Good thermal, oxidative stability & excellent weather ability. Modification may be of two types: A. Co-polymerisation: EPDM LLDPE VLDPE EVA B. Chemical modification (post polymerisation modification): Chlorinated polyethylene (CPE) Chlorosulphonated polyethylene (CSM)
Chlorinated polyethylene (CPE)
Introduction of Cl group has various opposing effects: i) Reduces chain regularity (Cl group is introduced randomly), thereby restricting the polymer to crystallize which tends to increase rubberiness. ii) It increases interchain attraction . iii) Imparts good oil resistance and flame resistance properties. iv) Compatibility with polar rubber increases. Commercial products:
Commercially available CPE : 26-42% chlorination Normal grade: 36% Cl content, ML (1+4) @ 120C : 85
Chlorinated polyethylene (CPE)
Manufacturing process: TYRIN CPE products are made by chlorinating polyethylene (PE) to form CPE.
Cl content 8% 25%
Brittleness temp (C) < -70 < -70
RT structure Crystalline Mainly amorphous
Physical form --Rubbery
Softening point (C) 69 20
40% 54% 60%
~ -70 + 20 + 40
Amorphous Amorphous Amorphous
Soft & flexible Rigid Rigid & brittle
20 52 67
Chlorinated polyethylene (CPE)
Processing of CPE: CPE can be processed in conventional elastomer processing equipment like internal mixers, 2 roll mill etc. Conventional mixing technique is adopted, otherwise for highly loaded stocks upside down technique is followed. Thermal softening during processing is a reversible phenomenon. Good bin stability. Compounding of CPE: 1. CPE polymer type 2. Performance requirements 3. Compounding ingredients 4. Total cost of producing the final article
Chlorinated polyethylene (CPE)
Curing of CPE: Generally peroxides are used for curing for CPE. Most commonly used are: I. Dicumyl peroxide II. Bis(t-butylperoxyisopropyl)benzene III. 2,5-dimethyl-2,5-di(t-butylperoxy)hexane Theses peroxides are used in conjunction with a promoter like triallylcyanurate (TAC) Non peroxide curing involves thiadiazole derivatives in conjunction with anilinebutyraldehyde derivatives. MgO is used as a heat stabiliser. To avoid moisture sensitivity lead stabilisers may be used. Expensive polar plasticizers like DOP, DOS are used.
Chlorinated polyethylene (CPE)
Cable heater jacket formulation using CPE (90C rating): Ingredients Tyrin CM 0136 CaCO3 Di isononyl phthalate Amino silane functionalised hydrated aluminium silicate MgO Polymerised 1,2 dihydo 2,2,4 trimethyl quinoline Bis(t-butylperoxyisopropyl)benzene dispersed on clay (40% active) 85% Sb2O3 TAC Functions Base polymer Filler Plasticizer Amount (phr) 100 50 25
Applications of CPE: I. Wire and cable application (good heat and flame resistance property) II. Automotive hose covering III. Available in powder form : impact modifiers for plastics.
Waterproofing membrane
Cable insulation
Chloro-sulphonated polyethylene(CSM) Chlorosulphonation: The CSM rubber contains both chlorine and sulphonyl chloride (-SO2Cl) group (Acts as a cure site).Chlorosulphonation is brought about by the Reed-Horn reaction that involves co reaction of SO2 and Cl2 in presence of light. h Cl2 RH + Cl R + SO2 RSO2 + Cl2 R + Cl2 2 Cl R + HCl RSO2 RSO2Cl + Cl RCl + Cl
Dry grade polymers (normal rubber compounds) Solution grade polymers (coating application) General characteristics: I. Very good weather ability, oxygen and ozone resistance owing to its saturated backbone. II. The balance of chain flexibility and Cl content is such that the material exists in rubbery range. III. Presence of chlorine confers hydrocarbon oil resistance and flame resistance. IV. Very good heat resistance with an EE rating by ASTM D 2000 being obtainable.
Chloro-sulphonated polyethylene(CSM) Effect of chlorine content:
Heat and oil resistance of various elastomer:
Modified CSM (ACSM Acsium)
Alkylated Chloro-sulphonated polyethylene:
% sulphur : ~ 1.31% % Chlorine : ~ 36%
Low temperature property is better than CSM Hydrocarbon oil resistance property is inferior.
Compounding and vulcanization of CSM
HYPALON should be mixed and processed at as low a temperature as is practical.
Due to the presence of highly reactive sulphonyl group a wide variety of curing system can be applied: I. Metallic oxide + rubber accl II. Metallic oxide + polyfunctional alcohol + rubber accl III. Epoxy resin + rubber accl IV. Metallic oxide + bismaleimide V. Metallic oxide + peroxide coagent ZnO is never used as if may lead to the formation of ZnCl2 which will degrade the polymer. In case of diene rubber ZnO may be used with proper care. Stearic acid can be used as a mould releasing agent..
CSM industrial roll cover : heavy duty mining cable jacket
Cured at 152C for 20 mins Hardness: 71 shore A Tensile strength: 15.2 Mpa %EAB : 275
Applications of CSM 1. 2. 3. 4. Coated fabric and sheeting Wire and cable application Hoses and automotive application Heater hose, radiator hose, fuel hose.,
References 1. J.A.Brydson, Rubbery Materials and Their Compounds, 4th edition, Elsevier Applied Science, New York 1990. 2. The Vanderbilt Rubber Handbook, R.T Vanderbilt Company Inc. 13th edition,30, Winfield Street, 1990 3. C.M.Blow and C. Hepburn, Rubber Technology and Manufacture, 2nd edition Butterworth Scientific, London, 1982.
