PVC Degradation and Stabilization

PVC Degradation and Stabilization

Author: George Wypych
ISBN 978-1-895198-39-3 

Published: 2008
Second edition
Pages: 442
Figures: 275
Tables: 66
With the global renewal of interest in PVC, this book is well timed, considering that PVC stabilization is the most important aspect of its formulation and performance.

Only four books have been published on PVC degradation and stabilization (the last one in the 1980s), and two of them are by the author of this book.

Separate chapters review information on chemical structure, PVC manufacturing technology, morphology, degradation by thermal energy, and UV, gamma, and other forms of radiation, mechanodegradation, chemical degradation, analytic methods used in studying of degradative and stabilization processes, stabilization, and effect of PVC and its additives on health, safety and environment.

This book contains an analysis of all essential papers published until recently on the above subject. It either locates the answers to relevant questions and offers solutions or gives references in which such answers can be found.

PVC Degradation and Stabilization is must have for chemists, engineers, scientists, university teachers and students, designers, material scientists, environmental chemists, and lawyers who work with polyvinyl chloride and its additives or have any interest in these products. This book is the one authoritative source on the subject.

PVC has a long history of development which began nearly 100 years ago with the patenting of the concepts of emulsion and suspension polymerization, the development of the industrial process of vinyl chloride synthesis, and patents on its plasticization, followed by the development of stabilization about 75 years ago. PVC has known rapid growth to utmost prominence and dramatic downfall almost to elimination, and it finally has regained a deserved, second position among commercial polymers.
PVC owes both its prominence and its downfall to research: meticulous, cutting-edge studies and unscrupulous bad science which stops progress and derails achievements.
PVC degradation during processing and use was always one of the essential elements of PVC science and technology. Many approaches to stabilization changed and some groups of stabilizers are not used in new production. This book was written to show new trends and directions. It also contains clearly indicated information about past stabilizers, which is needed in order to understand the principles of stabilization and effective recycling.
For me, it has been an interesting experience to actively participate in the growth of this branch of science and summarize its achievements and the directions which it faces now, here and in my two previous books, written 25 years ago. I hope the clarity and completeness of the description of research findings as we know them today will help in further research and, most importantly, lead to successful and responsible practical applications of additives in PVC processing and applications.

George Wypych
Toronto, May 8, 2008

1 Chemical Structure of PVC

1.1 Repeat structures and their basic organic chemistry
1.1.1 Bronsted acid source with controllable emission
1.2 Molecular weight and its distribution
1.2.1 Kuhn-Mark-Houwink-Sakurada
1.2.2 Fikentscher K number
1.2.3 Chain length
1.3 Prediction of formation of irregular segments
1.3.1 Ab initio
1.3.2 Monte Carlo
1.4 Irregular segments
1.4.1 Branches
1.4.2 Tertiary chlorine
1.4.3 Unsaturations
1.4.4 Oxygen containing groups Ketochloroallyl groups a- and b-carbonyl groups
1.4.5 Head-to-head structures
1.4.5 Initiator rests
1.4.6 Transfer agent rests
1.4.8 Defects introduced during processing
1.4.9 PVC having increased stability

2 PVC Manufacture Technology
2.1 Monomer
2.2 Basic Steps of Radical Polymerization
2.2.1 Initiation
2.2.2 Propagation
2.2.3 Termination
2.2.4 Chain transfer to monomer
2.3 Polymerization technology
2.3.1 Suspension
2.3.2 Paste resin manufacturing processes
2.3.3 Bulk
2.3.4 Solution
2.4 Polymerization conditions and PVC properties

3 PVC Morphology
3.1. Molecular weight of polymer (chain length)
3.2. Configuration and conformation
3.3. Chain folds
3.4. Chain thickness
3.5 Entanglements
3.6 Crystalline structure
3.7 Grain morphology
3.7.1 Stages of morphology development during manufacture Suspension polymerization Paste grades manufacture Bulk polymerization
3.7.2 Effect of morphology on degradation

4 Principles of Thermal Degradation
4.1 The reasons for polymer instability
4.1.1 Structural defects Branches Tertiary chlorine Unstaturations Oxygen containing groups Head-to-head structures Morphology
4.1.2 Polymerization residue Initiator rests Transfer agent rests Polymerization additives
4.1.3 Metal derivatives Metal chlorides Copper and its oxide
4.1.4 Hydrogen chloride 14
4.1.5 Impurities
4.1.6 Shear
4.1.7 Temperature
4.1.8 Surrounding atmosphere
4.1.9 Additives
4.2 Mechanisms of thermal degradation
4.2.1 Molecular mechanism
4.2.2 Amer-Shapiro mechanism
4.2.3 Six-center concerted mechanism
4.2.4 Activation enthalpy
4.2.5 Radical-chain theory
4.2.6 Ionic
4.2.7 Polaron
4.2.8 Degenerated branching
4.2.9 Transition state theory
4.2.10 Recapitulation
4.3 Kinetics
4.3.1 Initiation
4.3.2 Propagation
4.3.3 Termination
4.4 Results of thermal degradation
4.4.1 Volatiles
4.4.2 Weight loss
4.4.3 Char formation
4.4.4 Ash content
4.4.5 Thermal lifetime
4.4.6 Optical properties Color change Extinction coefficient Absorbance
4.4.7 Molecular weight
4.4.8 Mechanical properties
4.4.9 Electric properties
4.5 Effect of additives
4.5.1 Blend polymers ABS Chlorinated polyethylene, CPE Epoxidized butadiene/styrene block copolymer Epoxidized natural rubber Ethylene vinyl acetate, EVA High impact polystyrene, HIPS Methylmethacrylate-butadiene-styrene Nitrile rubber, NBR Oxidized polyethylene, OPE Polyacrylate Polyacrylonitrile Polyamide Polyaniline, PANI Polycarbonate, PC Polyethylene, PE Poly(methyl methacrylate), PMMA Poly(N-vinyl-2-pyrrolidone), PVP Polysiloxane Polystyrene, PS Polythiophene Polyurethane Poly(vinyl acetate), PVAc Poly(vinyl alcohol), PVA Poly(vinyl butyral), PVB SAN
4.5.2 Antiblocking
4.5.3 Antistatics agents
4.5.4 Biocides and fungicides
4.5.5 Blowing agents
4.5.6 Fillers
4.5.7 Flame retardants
4.5.8 Impact modifiers
4.5.9 Lubricants
4.5.10 Pigments
4.5.11 Plasticizers
4.5.12 Process aids
4.5.13 Solvents
4.5.14 Stabilizers

5 Principles of UV Degradation
5.1 Reasons for polymer instability
5.1.1 Radiative energy
5.1.2 Radiation intensity
5.1.3 Radiation incidence
5.1.4 Absorption of radiation by materials
5.1.5 Bond structure
5.1.6 Thermal history
5.1.7 Photosensitizers
5.1.8 Wavelength sensitivity
5.1.9 Thermal variability
5.1.10 Pollutants
5.1.11 Laboratory degradation conditions
5.2 Mechanisms of degradation
5.2.1 Radical mechanism Photooxidation mechanism Mechanistic scheme Conformational mechanism Electronic-to-vibrational energy transfer Other contributions to the mechanism of photodegradation
5.3 Kinetics
5.3.1 Initiation
5.3.2 Propagation
5.3.3 Termination
5.4 Results of UV degradation
5.4.1 Photodiscoloration
5.4.2 Mechanical properties
5.4.3 Other properties
5.5 Effect of additives
5.5.1 Biocides and fungicides
5.5.2 Fillers
5.5.3 Flame retardants
5.5.4 Impact modifiers
5.5.5 Lubricants
5.5.6 Pigments and colorants Titanium dioxide Zinc oxide Iron-containing pigments
5.5.7 Plasticizers
5.5.8 Polymer blends
5.5.9 Solvents
5.5.10 Stabilizers

6 Principles of Degradation by γ-Radiation
6.1 The reasons for polymer instability
6.2 Mechanisms
6.3 Kinetics
6.4 Results
6.5 Effect of additives
6.5.1 Plasticizers
6.5.2 Fillers
6.5.3 Stabilizers

7 Degradation by Other Forms of Radiation
7.1 Argon plasma
7.2 b-radiation (electron beam)
7.3 Corona discharge
7.4 Ion (proton) beam
7.5 Laser
7.6 Metallization
7.7 Microwave
7.8 Neutron irradiation
7.9 Oxygen plasma
7.10 X-rays
7.11 Ultrasonic
8 Mechanodegradation

9 Chemical Degradation

9.1 methods of chemical dehydrochlorination
9.2. Kinetics and mechanisms of reaction

10 Analytical Methods
10.1 Heat stability test
10.1.1 Sample preparation
10.1.2 Kinetic studies of dehydrochlorination
10.1.3 Dehydrochlorination rate and optical changes
10.1.4 Degradation in solution
10.2 Thermogravimetric analysis
10.2.1 Differential scanning calorimetry, DSC
10.2.2 Mass loss
10.3 Combustion
10.4 Optical properties
10.5 Spectroscopic methods
10.5.1 Atomic absorption, AAS
10.5.2 Auger
10.5.3 Electron spin resonance, ESR
10.5.4 Fourier transform infrared, FTIR
10.5.5 Laser photopyroelectric effect spectrometry
10.5.6 Mass, MS
10.5.7 Mossbauer
10.5.8 Near-infrared, NIR
10.5.9 Nuclear magnetic resonance, NMR
10.5.10 Positron annihilation lifetime spectroscopy, PAS
10.5.11 Raman
10.5.12 Time-of-flight secondary ion mass spectrometry, ToF-SIMS
10.5.13 X-ray analysis Small angle light scattering, SAXS Wide angle light scattering, WAXS or WAXD
10.5.14 X-ray photoelectron spectroscopy, XPS
10.5.15 UV-visible
10.6 Chromatographic methods
10.1 Gas chromatography
10.6.2 Liquid chromatography
10.7 Mechanical properties
10.8 Other essential methods of testing
10.8.1 Action spectrum
10.8.2 Coulter counter
10.8.3 Gel content
10.8.4 Ozonolysis
10.8.5 Peroxide titration
10.8.6 Rheological studies
10.9 International standards

11 Principles of Stabilization
11.1 Functions of PVC stabilizers
11.1.1 Hydrogen chloride binding
11.1.2 Removal of reactive chlorine
11.1.3 Reactions with metal chlorides
11.1.4 Reactions with isolated unsaturations
11.1.5 Reaction with conjugated unsaturations
11.1.6 Decomposition of hydroperoxides
11.1.7 Removal of reactive radicals (chain breaking function)
11.1.8 UV screening
11.2 Theories
11.2.1 Frye and Horst
11.2.2 Application of the Debye-Hückel theory
11.2.3 Kinetic model of PVC stabilization
11.3 Stabilizer groups
11.3.1 Metal soaps
(The groups of stabilizers below are discussed according to the following breakdown: Properties and applications of commercial stabilizers  Mechanisms of action Costabilizers Research findings) Barium/zinc Calcium/zinc Magnesium/zinc Potassium/zinc Barium/cadmium Barium/cadmium/zinc
11.3.2 Lead stabilizers
11.3.3 Organotin stabilizers
11.3.4 Organic stabilizers Epoxidized compounds Phenolic antioxidants Multiketones Other costabilizers
11.3.5 UV stabilizers Organic UV absorbers Inorganic UV absorbers Hindered amine light stabilizers, HALS
11.3.6 Lubricants 

12 Health and safety and environmental impact
12.1 Toxic substance control
12.2. Carcinogenic effect
12.3 Teratogenic and mutagenic effect
12.4 Workplace exposure limits
12.5 Exposure from consumer products
12.6 Drinking water
12.7 Food regulatory acts
12.8 Toxicity of stabilizers

George Wypych has a Ph. D. in chemical engineering. His professional expertise includes both university teaching (full professor) and research & development. He has published 14 books: PVC Plastisols, (University Press); Polyvinylchloride Degradation, (Elsevier); Polyvinylchloride Stabilization, (Elsevier); Polymer Modified Textile Materials, (Wiley & Sons); Handbook of Material Weathering, 1st, 2nd, 3rd, and 4th Editions, (ChemTec Publishing); Handbook of Fillers, 1st and 2nd Editions, (ChemTec Publishing); Recycling of PVC, (ChemTec Publishing); Weathering of Plastics. Testing to Mirror Real Life Performance, (Plastics Design Library), Handbook of Solvents, Handbook of Plasticizers, Handbook of Antistatics, Handbook of Antiblocking, Release, and Slip Additives, PVC Degradation & Stabilization, The PVC Formulary (all by ChemTec Publishing), 47 scientific papers, and he has obtained 16 patents. He specializes in polymer additives, polymer processing and formulation, material durability and the development of sealants and coatings. He is included in the Dictionary of International Biography, Who's Who in Plastics and Polymers, Who's Who in Engineering, and was selected International Man of the Year 1996-1997 in recognition for his services to education.