MATERIALS, TECHNOLOGIES AND INDUSTRIAL PLANTS (UNIT 2)
Learning outcomes of the course unit
Knowledge and understanding
At the end of the course, the student will acquire the basic knowledge on the properties of non metallic material for packaging.
Applying knowledge and understanding
The student will be able to make proper choices in the selection of the many packaging options available today. Thanks to the lab experiences, the students will be able to use the acquired knowledge to analyze and process numerical data to support their decision-making.
On passing the exam, the student will develop the ability to critically evaluate the analytical data of the mechanical behavior of a packaging material to predict its behavior in work, as well as the ability to interpret the data of the controls.
On passing the exam, the student will acquire adequate language property as regards the technical terminology specific of the course.
Students who take the course will be able to deepen their knowledge in the field of materials for food packaging, by consulting on their own specialized texts or dissemination journals, even outside of the topics covered closely in class.
Knowledge of Chemistry and Material Science are useful bases for the operation of the course.
Course contents summary
INTRODUCTION. Terminology. Purpose and characteristics of packaging.
CHEMICAL PROPERTIES. Chemical structure, characteristics and
resistance of materials.
PHYSICAL PROPERTIES. Thermal properties. Optical properties. The
behavior of a material to ionizing radiation. The behavior of a material
exposed to microwaves. Mechanical properties.
PACKAGING MATERIALS. Glass. Plastics. Cellulosic materials. Paper and paperboard.
Chemical properties of packaging materials. Chemical structure and characteristics of the materials. Atomic constituents. Bonds between atoms. Molecular bonds. Molecular organization. Chemical properties of interest to the packaging materials. Resistance to oils and fats. Environmental stress cracking resistance. Burning behavior. Biodegradation, biodeterioration, biotoxicity, biofilm formation. Physical properties of packaging materials: surface properties, thermal, mechanical and electromagnetic. Surface properties. Surface tension, wettability and adhesion. Methods of measurement of surface properties. Relationship between contact angle and surface energy. Modification of the surface energy. Thermal properties. Thermal conductivity. Heat capacity and specific heat. Coefficients of thermal expansion. Useful temperature range (range of use). Calorific value and energy content. Transition temperatures. Mechanical properties. Creep resistance (friction). Mechanical strength. Properties related to dynamic stress. Shock absorption properties (cushioning properties). Electromagnetic properties. Interactions between electromagnetic radiation and matter. Electromagnetic properties of the packaging materials in the visible and ultraviolet regions. Behavior of a material subjected to ionizing radiation. Behavior of a material irradiated with microwaves. Density and related properties. Density. Weight. Glass and glass packaging. Chemical structure of the glass. Production of glass. Physical and chemical properties of the glass. Mechanical properties. Thermal properties. Optical properties. Chemical reactivity. Technology of production of glass containers. Press-blow technique. Blow-blow technique. Annealing. Quality Control. Reinforcement techniques of glass containers. Ceramics. Metals and metal packaging. Aluminum. Production and characteristics of aluminum alloys. Technology of production of manufactured of aluminum. Tinplate and other coated steels. Production of steel and their characteristics. Structure, properties and manufacture of tinplate. Structure, properties and production of chrome strip. Other coated steels. Stainless steels. Metal containers. Deformable tubes. Aerosol containers. Kegs (barrels) in stainless steel. Drums and barrels. Jars and canisters. Interior protective coatings. Corrosion of metals. Cellulosic materials and packaging. Morphological structure of cellulose fibers. Chemical structure of the cellulose fibers. Lignin. Hemicelluloses. Cellulose. Paper and cardboard. Raw materials for the production of paper and paperboard. Production technologies. Additives used in the production of paper and board. Special papers. Paper properties. Corrugated cardboard. Stiff cardboard. Coated Board. Cellulose modeled. Cellulose pulp. Cellophane. Regenerated cellulose. Envelopes and paper bags. Folding boxes. Corrugated cardboard boxes. Materials and plastic packaging. Structure and properties of plastics. Nature of raw materials. Polymerization mechanism. Tacticity. Molecular weight. Reaction to heat. Glass transition temperature. Morphology. Structural organization. Polymer blends and polymer alloys. Structural changes in the plastics industry. Orientation. Shrinking. Main polymers used in food packaging. Most common polymers. Polymers sealing. Polymers with high gas barrier. Less common polymers. Symbols and abbreviations of polymers and some of their characteristics. Packaging materials and plastic packaging. Additives of plastics. Films or films. Trays and hollow injection molded. Thermoformed trays and hollow bodies. Bottles and plastic bottles. Foamed plastics.
Luciano Piergiovanni, Sara Limbo "Food packaging. Materiali, tecnologie e qualità degli alimenti". Springer-Verlag Italia, 2010.
G. L. Robertson “Food Packaging ans Shelf life: A practical Guide”. CRC Press / Taylor & Francis Group, 2009.
The course includes:
(i) theoretical lectures made with the aid of multimedia systems. The didactic material is uploaded at the start of the course on the platform “Elly” (http://elly.dia.unipr.it);
(ii) experimental labs on the material characterization;
(iii) educational visits.
The lab activity will be presented in a short report by each group (2/3 students) and it will be discussed during the course.
Assessment methods and criteria
Written examination which consists of 5 open questions to each of which are assigned up to 6 points. The written examination (2 hrs) is passed if students gain at least 18/30.