Chemical Sciences

IOLANDA FRANCOLINI

The course aims to provide the Student with the basic knowledge of Macromolecular Science. Definitions and classifications of Macromolecules will be discussed as well as polymerization mechanisms and processes, their properties in solution, morphological aspects of the solid state, thermal behaviors, mechanical and rheological properties. The student will acquire skills regarding basic principles and terminology of Macromolecular Science, polymerization mechanisms and processes, the different types of polymer chains, macromolecular stereochemistry, their molecular weight characteristics (heterogeneity and distribution, methods of determination) and average size, thermodynamics of polymer solutions, the molten and solid state of polymeric materials, their crystallization, thermal and mechanical properties and elastic and viscoelastic rheological behaviors, as well as on classical thermodynamics and statistics of the ideal elastomer. Laboratory experiments are also planned to acquire further skills regarding the synthesis and characterization of polymers.


Finally, the students will gain ability to face challenges of the Chemical Industry of polymer materials thanks to their knowledge about correlations between structure and physical properties of polymers as well as will possess the necessary background to attend specialist courses to continue its academic formation.

At the end of the Course of Foundations of Macromolecular Sciences, the student must:

- Know the differences between constitution, conformation and configuration of polymers
- Know the fundamentals of the synthesis of polymeric materials;
- Know the main thermal transitions of polymers
- Know the morphology of the crystalline phase of polymeric materials
- Know the main characterization techniques of polymeric materials;
- Know and be able to write the repeating units of the most common polymers

There are no prerequisites but for a better understanding of the topics of the course, it is considered essential to have basic knowledge of Organic Chemistry I.

Definitions and classifications of Macromolecules
Configurational characteristics of polymers. Definition of Macromolecule, Polydispersity, Monomer, Repeating unit, Degree of polymerization, Oligomers, Telomers, Telechelic Polymers, Polyelectrolytes, Macroions and Macroradicals.
Types of macromolecules
Polymers of natural origin or synthetic. Homopolymers and copolymers: Linear homopolymers, Linear alternating copolymers, Linear block copolymers, Statistical linear copolymers. Branched polymers; Crosslinked polymers; Ladder polymers; Comb polymers (comb); Dendrimers.
Classification according to mechanical properties.
Configurational characteristics of polymer chains
Polymers containing double bonds in the repeating unit; Polymers containing carbon atoms asymmetric in the repeating unit; Isotactic polymers; Syndiotactic polymers; Ditactic polymers; Erythro-di-isotactic polymers; Threo-di-isotactic polymers; Erythro-di-syndiotactic polymers; Threo-disindiotactic polymers.
Conformational characteristics of polymer chains
The model of the random flight chain: Case of the chain with constrained bond angle, Case of the chain with constrained internal rotation angle; The characteristic ratio; The radius of gyration. Conformers or Rotamers or Conformational Isomers; Conformational degrees of freedom; The possible conformations; Semi-empirical calculations of potential energy for the determination of the possible conformations; Torsional Energy, Van der Waals Energy, Colombian Energy, Hydrogen Bond Energy; The coefficients of the potential functions; Potential energy map of n-butane; Map of the potential energy of polyethylene. Types of defects in the polymer chain; The various types of protein structure: primary, secondary, tertiary and quaternary structure.
Mechanisms and processes of polymer synthesis
Step-growth polymerizations: polycondensations, polyadditions, use of bifunctional monomers, polyfunctional monomers and obtaining crosslinked, branched, star polymers; reaction mechanism; Conversion degree (p) and numerical average degree (Xn); Polymerization kinetics.
Chain Polymerizations: Radicals, Initiation, Propagation, Termination; Structure of polymers from radical polymerization: head-to-tail and head-to-head linkages, branching, stereoregularity; Self-acceleration phenomenon; Inhibition and Delay; Molecular weight distribution; Effect of Temperature; Ionic Polymerizations (Cationic, Anionic): Initiators, Monomers, Solvents; Ex. of polymerization; Stereospecific (coordination) polymerizations Ziegler Natta: Mechanism; Notes on Polymerization processes.
Notes on the behavior of polymers in solution
Ideal sand regular Solutions; Polymer solutions; Variation of mixing entropy; Volume fractions; Flory temperature; Volume excluded.
Molecular weights, their distribution and techniques for their determination
Number average molecular weight; Measurement techniques of Mn. Weight Average Molecular Weight, Mw Measurement Techniques: Light Scattering, Case of Light Scattering in a Gas, Case of Light Scattering in a Solution with Point Particles, Debye Equation, Case of Light Scattering in a Solution with Particles non-point-like, Zimm Plot. Ultracentrifugation, Average molecular weight z, Sedimentation rate. Viscosity average molecular weight, Huggins and Kramer equations, Mark-Houwink-Sakurada equation. Gel Permeation Chromatography, Average Molecular Weight GPC.

Morphological aspects related to the solid state of polymeric materials
The fringed micelle model. The crystalline structure of polymers. The single crystals; Types of folds; Crystallization from solution. Crystallization from the melt: Spherulites. Annealing, Roe's experiments.
Thermal behavior of polymeric materials
Thermal transitions of polymeric materials: 1st order thermodynamic transitions; Determination of the thermodynamic or equilibrium melting temperature; Causes of Melt Peak Enlargement; Dependence of Tm on the heating rate; Thomson-Gibbs equation; Tm-structure correlations; The change in entropy at fusion; 2nd order thermodynamic transitions; The glass transition. Effects of chemical structure on Tg; Effect of polarity on Tg; Effect of molecular weight on Tg; Effect of crosslinking on Tg.
Mechanical and rheological properties of materials
Types of behavior of materials; Types of solicitations; Types of measures. Stress-strain diagram; Characteristics of stress-strain curves; Fiber stress-strain curves; Deformations and free energy. Viscous flow: Dynamic and kinematic viscosity, Newtonian behavior, Pseudoplastic behavior, Dilatant behavior, Plastic behavior, Time-dependent behaviors, Measurement techniques; Dependence of viscosity on molecular weight, Dependence of viscosity on branching and polydispersity, Dependence of viscosity on temperature; WLF equation. Dynamo-mechanical technique and complex module. Elastomers, The typical behavior of elastomers, Stress-strain curve of the elastomer, Elasticity of entropy.
Examples of polymers for advanced applications

Ciardelli F., Farina M., Giusti P., Cesca S., Macromolecole. Scienza e Tecnologia Vol. I e II, Pacini Editore
Guaita M., Ciardelli F., La Mantia F., Pedemonte E., Fondamenti di Scienza dei Polimeri, Pacini Editore.
Young R. J., Lovell P. A., Introduction to Polymers, CRC Press.
Flory P. J., Principles of Polymer Chemistry, Cornell University Press

The lessons will be delivered in the classroom, using conventional methods, employing computer support and slides. Practical exercises will be carried out in the laboratory. After the experimental activity, students are required to prepare a report to be submitted to the teacher before the exam.

Class attendance is optional. The attendance of laboratory exercises is mandatory.

The written exam will include open-ended questions and a numerical exercise

1. Describe the difference between Constitution, Configuration and Conformation of a macromolecule
2. Define what does tactical polymer/atactic polymer mean
3. Indicate the main differences between step and chain polymerizations
4. Write the repeating unit of Polyethylene terephthalate
5. Define the glass transition