Macromolecular Chemistry
A.Y. 2022/2023
Learning objectives
The fundamental learning objective of this course is to provide Students with a clear picture of the basic concepts of polymer chemistry required to be able to attend advanced courses in polymer science. For this reason, in the initial phase of the course, emphasis will be placed on the definitions of the science of polymers useful for addressing the study of these materials.
Students will learn about the polymerization mechanisms that are used in the industrial synthesis of polymers, including the mechanism of step-wise polymerization, polymerizations with radical and ionic chain mechanisms and stereospecific polymerization mechanisms.
Students will learn the characteristics of the amorphous and crystalline solid state of polymers, the definitions of the transition temperatures typical of these phases and their dependence on the structural parameters of polymers.
Finally, Students will learn the classical methods of determining molecular weights.
The aim of the laboratory course will be to put into practice the topics covered in the theoretical section of the course by individually carrying out polymer synthesis tests using different types of mechanisms, including step-wise, radical and anionic mechanism. Students will also learn the basic procedures for the purification of polymers, for their structural analysis and for the determination of their molecular weights.
Students will learn about the polymerization mechanisms that are used in the industrial synthesis of polymers, including the mechanism of step-wise polymerization, polymerizations with radical and ionic chain mechanisms and stereospecific polymerization mechanisms.
Students will learn the characteristics of the amorphous and crystalline solid state of polymers, the definitions of the transition temperatures typical of these phases and their dependence on the structural parameters of polymers.
Finally, Students will learn the classical methods of determining molecular weights.
The aim of the laboratory course will be to put into practice the topics covered in the theoretical section of the course by individually carrying out polymer synthesis tests using different types of mechanisms, including step-wise, radical and anionic mechanism. Students will also learn the basic procedures for the purification of polymers, for their structural analysis and for the determination of their molecular weights.
Expected learning outcomes
At the end of the course, the Student will be able to:
1. Define the basic concepts and terms essential for the study of polymer science.
2. Identify the classes of polymerizable monomers with the synthetic mechanisms described.
3. Describe the fundamental mechanisms used for the industrial synthesis of polymers, including, in particular, step-wise polymerization, chain polymerizations with radical, ionic and coordinated insertion mechanisms.
4. Predict the conversion dependence of the average degree of polymerization in the different polymerization processes.
5. Know the industrial processes used for the synthesis of polymers by radical mechanism.
6. Understand the different characteristics of the amorphous and crystalline solid state of polymers and the influence of the transition temperatures typical of these states on the physical properties and workability of the polymers.
7. Predict the glass transition temperature of polymers by knowing their structural features.
8. Know the basic techniques of purification and structural characterization of polymers.
9. Know how to experimentally determine the molecular weights of polymers using SEC chromatography.
1. Define the basic concepts and terms essential for the study of polymer science.
2. Identify the classes of polymerizable monomers with the synthetic mechanisms described.
3. Describe the fundamental mechanisms used for the industrial synthesis of polymers, including, in particular, step-wise polymerization, chain polymerizations with radical, ionic and coordinated insertion mechanisms.
4. Predict the conversion dependence of the average degree of polymerization in the different polymerization processes.
5. Know the industrial processes used for the synthesis of polymers by radical mechanism.
6. Understand the different characteristics of the amorphous and crystalline solid state of polymers and the influence of the transition temperatures typical of these states on the physical properties and workability of the polymers.
7. Predict the glass transition temperature of polymers by knowing their structural features.
8. Know the basic techniques of purification and structural characterization of polymers.
9. Know how to experimentally determine the molecular weights of polymers using SEC chromatography.
Lesson period: First semester
Assessment methods: Esame
Assessment result: voto verbalizzato in trentesimi
Single course
This course cannot be attended as a single course. Please check our list of single courses to find the ones available for enrolment.
Course syllabus and organization
Single session
Responsible
Lesson period
First semester
Course syllabus
THEORETICAL
1. Introduction to polymer science
Definitions of polymer, monomer, macromolecule, homopolymer, copolymer. Plastics and their relevance. Natural, synthetic and artificial polymers. Inorganic polymers. Classification of polymers on the basis of the chemical structure they belong to. Molecular architectures. Classification of copolymers (statistical, block, graft, alternating) and their relevance. Phase separation in block copolymers. Structure of polymers: regioisomerism, geometric isomerism, configurations and conformations of polymers. Polymeric architectures. Definition of molecular weight of a polymer; definition of number and weight averages and molecular weight distribution. Examples of calculation of the number and weight average molecular weights of polymers.
2. Step-wise polymerization mechanism
Classification of monomers polymerizable by this mechanism: bifunctional monomers of type A-B; mixtures of monomers with two identical functions, A-A / B-B. Polycondensation and polyaddition polymers structures of industrial interest. Qualitative dependence of the degree of polymerization on the conversion and the ratio of the reactants. Use of reaction catalysts. Definition of numeral average degree of polymerization. Examples of calculating the degree of polymerization. Dependence of the average degree of polymerization on the reaction parameters (conversion, ratio of monomers, presence of monofunctional reagents). Kinetics of step-by-step polymerization in the presence and absence of catalysts.
2. Radical polymerization mechanism
Classification of polymerizable monomers by this mechanism: vinyl monomers; because olefins do not normally polymerize by radical polymerization. General characteristics of the process: a) polymerization with chain mechanism; b) subdivision into three basic stages, such as beginning, propagation and termination; c) non-stereospecific addition reactions. Thermodynamics of polymerization reactions with radical mechanisms: exothermic reactions. Concentrations of reactive species. Initiation reaction by: a) thermal, photochemical or electrochemical decomposition of initiators; b) spontaneous dissociation of the monomer (styrene and methyl methacrylate); c) redox reactions. Chain transfer reaction and molecular weight control of polymers. Kinetics of radical polymerization: stationary stage hypothesis. Dependence of the numeral average degree of polymerization on the reaction parameters. Chain transfer: Mayo equation. Reaction of inhibition and delay. Freezing or self-acceleration effect.
3. Industrial polymerization processes with radical mechanism
Classification of polymerization processes with radical mechanisms: solution, mass, suspension and emulsion. Relevant aspects of the solution and bulk polymerization. Suspension polymerization: description of the process and role of the protective colloid. Influence of process parameters. Molecular weight trend compared to mass polymerization. Emulsion polymerization: definition of surfactant, micelle, micellar critical concentration, emulsion. Heterophasic system in emulsion polymerization processes: co-presence of monomer in solution, monomer drops, micelles and polymeric particles. Location of polymerization and diffusive control of the process. Phases of the polymerization rate. Dependence of the numeral average degree of polymerization on the surfactant concentration.
4. Polymerizations with ionic mechanism
Polymerizable monomers. Main characteristics of polymerization mechanisms with ionic intermediates: solvent effect, reaction rate, absence of the term reaction. Polymerization with cationic mechanism: classification of the main classes of initiators, term reaction and chain transfer. Polymerization with anionic mechanism: carbanionic initiators; absence of the chain transfer and termination reaction. Living nature of the polymerization with anionic mechanism. Dependence of the molecular weight on the monomer / initiator ratio.
5. Polymerizations with coordination mechanism
Polymerizable monomers with coordinated mechanism: olefins. Composition of Ziegler / Natta type catalysts. Main transition and non-transition metals used Polymerization mechanism by polyinsertion. Steric control of the polymerization reaction: iso- and syndiospecific catalysts. 1st, 2nd and 3rd generation catalysts: choice of substrate and use of the 3rd component. Term reaction and chain transfer. Reactivity order of monomers (steric effects) and regioselectivity of the insertion reaction. Introduction to metallocene catalysts.
6. Size Exclusion Chromatography (SEC) - size exclusion chromatography
Definition of Size Exclusion Chromatography: Gel Permeation Chromatography and Gel Filtration Chromatography. Physical principle of operation: nature of the stationary phase; fractionation of polymers with wide molecular weight distribution on the basis of the hydrodynamic volume of the macromolecules in the eluent. Calibration of a SEC column system: nature of standards and calibration curve. Limitations in the use of standards with a different chemical structure than the analyte. Calculation of the numeral and weight average. Effect of the solvent: viscosity of the solvent, the interaction of the solvent with the solute. Effect of eluent flow.
7. Amorphous state of polymers
Definition of amorphous phase: absence of geometric order and molecular symmetry, absence of X-ray diffraction spectra. Amorphous polymers as homogeneous and isotropic materials. Definition of glass transition and glass transition temperature, Tg. Meaning of Tg: correlation with molecular dynamics; free volume. Tg as a transition of kinetic and non-thermodynamic nature. Gummy and glassy amorphous state. Definition of hard and brittle polymers and of viscoelastic polymers. Classification of the structural factors that influence the Tg value: internal factors (cohesive energy, polarity, structural flexibility) and external factors (presence of plasticizers, degree of cross-linking, presence of co-monomeric units). Examples of Tg values of commercial polymers. Physical aging of polymers.
8. Crystalline state of polymers
Definition of crystalline phase: geometric order and molecular symmetry; X-ray diffraction spectra. Definition of fusion and variation of the thermodynamic state functions at the fusion. Melting temperature. Structural requirements for a polymer to crystallize: regular primary structure, configurational and conformational order. Morphology classification of polymeric crystals: lamellae, spherulites, kebabs. Description of the lamellae: dimensions, geometry, and molecular folds; "Tie molecules". Spherulites: geometry, symmetry and coexistence with the amorphous phase. Growth of spherulites from lamellae. Structural hierarchy in spherulites. Examples of melting temperature values of commercial polymers.
LABORATORY SECTION
1. Synthesis of a linear polymer by step-wise polymerization in aqueous solution.
2. Synthesis of a polyhexamethylene maleate by bulk step-wise polymerization.
3. Synthesis of polystyrene by polymerization with free radical mechanism in suspension.
4. Synthesis of polymethylmethacrylate by polymerization with a radical mechanism in emulsion.
5. Synthesis of polyethylmethacrylate by polymerization with anionic mechanism.
6. Determination of the molecular weights of the synthesized linear polymers.
7. IR and 1H NMR analysis of the synthesized soluble polymers.
1. Introduction to polymer science
Definitions of polymer, monomer, macromolecule, homopolymer, copolymer. Plastics and their relevance. Natural, synthetic and artificial polymers. Inorganic polymers. Classification of polymers on the basis of the chemical structure they belong to. Molecular architectures. Classification of copolymers (statistical, block, graft, alternating) and their relevance. Phase separation in block copolymers. Structure of polymers: regioisomerism, geometric isomerism, configurations and conformations of polymers. Polymeric architectures. Definition of molecular weight of a polymer; definition of number and weight averages and molecular weight distribution. Examples of calculation of the number and weight average molecular weights of polymers.
2. Step-wise polymerization mechanism
Classification of monomers polymerizable by this mechanism: bifunctional monomers of type A-B; mixtures of monomers with two identical functions, A-A / B-B. Polycondensation and polyaddition polymers structures of industrial interest. Qualitative dependence of the degree of polymerization on the conversion and the ratio of the reactants. Use of reaction catalysts. Definition of numeral average degree of polymerization. Examples of calculating the degree of polymerization. Dependence of the average degree of polymerization on the reaction parameters (conversion, ratio of monomers, presence of monofunctional reagents). Kinetics of step-by-step polymerization in the presence and absence of catalysts.
2. Radical polymerization mechanism
Classification of polymerizable monomers by this mechanism: vinyl monomers; because olefins do not normally polymerize by radical polymerization. General characteristics of the process: a) polymerization with chain mechanism; b) subdivision into three basic stages, such as beginning, propagation and termination; c) non-stereospecific addition reactions. Thermodynamics of polymerization reactions with radical mechanisms: exothermic reactions. Concentrations of reactive species. Initiation reaction by: a) thermal, photochemical or electrochemical decomposition of initiators; b) spontaneous dissociation of the monomer (styrene and methyl methacrylate); c) redox reactions. Chain transfer reaction and molecular weight control of polymers. Kinetics of radical polymerization: stationary stage hypothesis. Dependence of the numeral average degree of polymerization on the reaction parameters. Chain transfer: Mayo equation. Reaction of inhibition and delay. Freezing or self-acceleration effect.
3. Industrial polymerization processes with radical mechanism
Classification of polymerization processes with radical mechanisms: solution, mass, suspension and emulsion. Relevant aspects of the solution and bulk polymerization. Suspension polymerization: description of the process and role of the protective colloid. Influence of process parameters. Molecular weight trend compared to mass polymerization. Emulsion polymerization: definition of surfactant, micelle, micellar critical concentration, emulsion. Heterophasic system in emulsion polymerization processes: co-presence of monomer in solution, monomer drops, micelles and polymeric particles. Location of polymerization and diffusive control of the process. Phases of the polymerization rate. Dependence of the numeral average degree of polymerization on the surfactant concentration.
4. Polymerizations with ionic mechanism
Polymerizable monomers. Main characteristics of polymerization mechanisms with ionic intermediates: solvent effect, reaction rate, absence of the term reaction. Polymerization with cationic mechanism: classification of the main classes of initiators, term reaction and chain transfer. Polymerization with anionic mechanism: carbanionic initiators; absence of the chain transfer and termination reaction. Living nature of the polymerization with anionic mechanism. Dependence of the molecular weight on the monomer / initiator ratio.
5. Polymerizations with coordination mechanism
Polymerizable monomers with coordinated mechanism: olefins. Composition of Ziegler / Natta type catalysts. Main transition and non-transition metals used Polymerization mechanism by polyinsertion. Steric control of the polymerization reaction: iso- and syndiospecific catalysts. 1st, 2nd and 3rd generation catalysts: choice of substrate and use of the 3rd component. Term reaction and chain transfer. Reactivity order of monomers (steric effects) and regioselectivity of the insertion reaction. Introduction to metallocene catalysts.
6. Size Exclusion Chromatography (SEC) - size exclusion chromatography
Definition of Size Exclusion Chromatography: Gel Permeation Chromatography and Gel Filtration Chromatography. Physical principle of operation: nature of the stationary phase; fractionation of polymers with wide molecular weight distribution on the basis of the hydrodynamic volume of the macromolecules in the eluent. Calibration of a SEC column system: nature of standards and calibration curve. Limitations in the use of standards with a different chemical structure than the analyte. Calculation of the numeral and weight average. Effect of the solvent: viscosity of the solvent, the interaction of the solvent with the solute. Effect of eluent flow.
7. Amorphous state of polymers
Definition of amorphous phase: absence of geometric order and molecular symmetry, absence of X-ray diffraction spectra. Amorphous polymers as homogeneous and isotropic materials. Definition of glass transition and glass transition temperature, Tg. Meaning of Tg: correlation with molecular dynamics; free volume. Tg as a transition of kinetic and non-thermodynamic nature. Gummy and glassy amorphous state. Definition of hard and brittle polymers and of viscoelastic polymers. Classification of the structural factors that influence the Tg value: internal factors (cohesive energy, polarity, structural flexibility) and external factors (presence of plasticizers, degree of cross-linking, presence of co-monomeric units). Examples of Tg values of commercial polymers. Physical aging of polymers.
8. Crystalline state of polymers
Definition of crystalline phase: geometric order and molecular symmetry; X-ray diffraction spectra. Definition of fusion and variation of the thermodynamic state functions at the fusion. Melting temperature. Structural requirements for a polymer to crystallize: regular primary structure, configurational and conformational order. Morphology classification of polymeric crystals: lamellae, spherulites, kebabs. Description of the lamellae: dimensions, geometry, and molecular folds; "Tie molecules". Spherulites: geometry, symmetry and coexistence with the amorphous phase. Growth of spherulites from lamellae. Structural hierarchy in spherulites. Examples of melting temperature values of commercial polymers.
LABORATORY SECTION
1. Synthesis of a linear polymer by step-wise polymerization in aqueous solution.
2. Synthesis of a polyhexamethylene maleate by bulk step-wise polymerization.
3. Synthesis of polystyrene by polymerization with free radical mechanism in suspension.
4. Synthesis of polymethylmethacrylate by polymerization with a radical mechanism in emulsion.
5. Synthesis of polyethylmethacrylate by polymerization with anionic mechanism.
6. Determination of the molecular weights of the synthesized linear polymers.
7. IR and 1H NMR analysis of the synthesized soluble polymers.
Prerequisites for admission
Basic knowledge of organic chemistry as provided in the Organic Chemistry I course of the same degree course. These include nomenclature, structure and general reactivity of aliphatic and aromatic compounds; reactivity of alkenes, alkynes, aliphatic halides, carboxylic acids; synthesis of esters, amides, urethanes, urea.
Teaching methods
Frontal lessons with the help of slides. The laboratory course will be preceded by introductory lectures. Each laboratory experience will be preceded by specific instructional lessons to be carried out before the start of the experience.
Teaching Resources
The content of the lessons is available in the copy of the slides shown during the lessons. These can be downloaded from the course website on the ARIEL platform.
Reference text:
"Textbook of Polymer Science", Fred Billmeyer.
"Chemistry and Physics of Modern Materials", Third Edition
J.M.G. Cowie, Valeria Arrighi, CRC Press.
Reference text:
"Textbook of Polymer Science", Fred Billmeyer.
"Chemistry and Physics of Modern Materials", Third Edition
J.M.G. Cowie, Valeria Arrighi, CRC Press.
Assessment methods and Criteria
The exam will consist of a written test in which the student is asked to answer open questions concerning the entire program of the course, both for the theoretical and laboratory section. The aim is to verify the acquired knowledge and understanding of the concepts discussed in both theoretical and laboratory sections. The score will vary from 18 to 30 proportionally to the correctness of the answers.
Assessment of knowledge of the laboratory section
· Description of the synthesis schemes and of the experimental conditions chosen.
· Interpretation of the IR and NMR spectra of the synthesized polymers.
· Determination of the calibration curve to be used in the SEC chromatographic analysis starting from the data provided.
· Setting of the calculation of the number and weight average molecular weights of a polymer sample starting from the chromatographic data provided.
Assessment of knowledge of the theoretical section
· General definitions and introductory concepts on polymer chemistry.
· Synthetic mechanisms of polymers, with reference to the families of polymerizable monomers, the chain transfer reactions, and to the trend and control of molecular weights in the various polymerization processes.
· Control of stereochemistry in polymerizations with coordinated mechanism.
· Definitions and characteristics of the solid-state of polymers.
· Knowledge of the main values of the glass transition and melting temperatures of the commercial polymers mentioned during the course.
Assessment of knowledge of the laboratory section
· Description of the synthesis schemes and of the experimental conditions chosen.
· Interpretation of the IR and NMR spectra of the synthesized polymers.
· Determination of the calibration curve to be used in the SEC chromatographic analysis starting from the data provided.
· Setting of the calculation of the number and weight average molecular weights of a polymer sample starting from the chromatographic data provided.
Assessment of knowledge of the theoretical section
· General definitions and introductory concepts on polymer chemistry.
· Synthetic mechanisms of polymers, with reference to the families of polymerizable monomers, the chain transfer reactions, and to the trend and control of molecular weights in the various polymerization processes.
· Control of stereochemistry in polymerizations with coordinated mechanism.
· Definitions and characteristics of the solid-state of polymers.
· Knowledge of the main values of the glass transition and melting temperatures of the commercial polymers mentioned during the course.
CHIM/04 - INDUSTRIAL CHEMISTRY - University credits: 6
Laboratories: 32 hours
Lessons: 32 hours
Lessons: 32 hours
Professor:
Ranucci Elisabetta
Shifts:
Professor:
Ranucci Elisabetta
Corso A
Professor:
Ranucci ElisabettaCorso B
Professor:
Ranucci ElisabettaEducational website(s)
Professor(s)
Reception:
Free time, preferable appointment by e-mail
Office 3rd floor Department of Chemistry