INTERNATIONAL FRANCHISING: FOCUS ON CENTRAL AND EASTERN EUROPE AND RUSSIA

This thesis discusses and analyzes international franchising and its introduction and development in the emerging democracies in Eastern Europe. After a general presentation of the franchise marketing method, the advantages and disadvantages to both parties of the franchise relationship are discussed. Attention is given to the alternatives available to foreign franchisors contemplating international franchising in the Eastern European region. The thesis further reviews the newly enacted foreign investment laws in six Eastern European countries - Hungary, Czech Republic, Poland, Bulgaria, Romania, and Russia - as they relate to the joint venture operations in the region and the attending legal issues. Review of the U.S. franchise laws is presented and their applicability to international franchise sales is discussed and analyzed

Recycling of Thermoset Materials and Thermoset-Based Composites: Challenge and Opportunity

Thermoset materials and their composites are characterized by a long life cycle with their main applications in aircrafts, wind turbines and constructions as insulating materials. Considering the importance of recovery and valorization of these materials at their end-of-life, avoiding landfilling, the interest concerning their recycling grows continuously. The thermoset materials and their composites, to be successfully recovered and valorized, must degrade their three-dimensional structures and recover the mono-oligomers and/or fillers. The thermoset materials could successfully degrade through thermal treatment at different temperatures (for example, above 1000 degrees C for incineration, ca. 500 degrees C for oxidation/combustion of organic constituents, etc.), chemical degradation by catalyst, irradiation with or without the presence of water, alcohol, etc., and mechanical recycling, obtaining fine particles that are useful as filler and/or reinforcement additives. Among these recycling methods, this mini-review focuses on the formulation and recovery method of innovative thermoset with in-build recyclability, i.e., materials having chemical links that could be degraded on-demand or containing dynamic covalent bonds to have re-processable and/or recyclable thermoset. This issue could be considered the future perspective in developing novel thermoset materials. The aim of this review is to get an overview of the state of the art in thermoset recycling and of the most commonly used thermoset composites, recovering valuable reinforcing fibers. Additionally, in this work, we also report not only known recycling routes for thermoset and thermoset-based composites, but also new and novel formulating strategies for producing thermosets with built-in recyclability, i.e., containing chemical-triggered on-demand links. This mini-review is also a valuable guide for educational purposes for students and specialized technicians in polymer production and recycling

A review of bioplastics and their adoption in the circular economy

The European Union is working towards the 2050 net-zero emissions goal and tackling the ever-growing environmental and sustainability crisis by implementing the European Green Deal. The shift towards a more sustainable society is intertwined with the production, use, and disposal of plastic in the European economy. Emissions generated by plastic production, plastic waste, littering and leakage in nature, insufficient recycling, are some of the issues addressed by the European Commission. Adoption of bioplastics–plastics that are biodegradable, bio-based, or both–is under assessment as one way to decouple society from the use of fossil resources, and to mitigate specific environmental risks related to plastic waste. In this work, we aim at reviewing the field of bioplastics, including standards and life cycle assessment studies, and discuss some of the challenges that can be currently identified with the adoption of these materials

Sustainable Materials Containing Biochar Particles: A Review

The conversion of polymer waste, food waste, and biomasses through thermochemical decomposition to fuels, syngas, and solid phase, named char/biochar particles, gives a second life to these waste materials, and this process has been widely investigated in the last two decades. The main thermochemical decomposition processes that have been explored are slow, fast, and flash pyrolysis, torrefaction, gasification, and hydrothermal liquefaction, which produce char/biochar particles that differ in their chemical and physical properties, i.e., their carbon-content, CHNOS compositions, porosity, and adsorption ability. Currently, the main proposed applications of the char/biochar particles are in the agricultural sector as fertilizers for soil retirement and water treatment, as well as use as high adsorption particles. Therefore, according to recently published papers, char/biochar particles could be successfully considered for the formulation of sustainable polymer and biopolymer-based composites. Additionally, in the last decade, these particles have also been proposed as suitable fillers for asphalts. Based on these findings, the current review gives a critical overview that highlights the advantages in using these novel particles as suitable additives and fillers, and at the same time, it shows some drawbacks in their use. Adding char/biochar particles in polymers and biopolymers significantly increases their elastic modulus, tensile strength, and flame and oxygen resistance, although composite ductility is significantly penalized. Unfortunately, due to the dark color of the char/biochar particles, all composites show brown-black coloration, and this issue limits the applications

Novel organo-modifier for thermally-stable polymer-layered silicate nanocomposites

A new novel approach for the stabilisation of polymer-clay nanocomposites has been investigated based on reacting chemically an antioxidant function, a hindered phenol moiety, with an organic modifier based on a quaternary ammonium salt. The chemically linked antioxidant-containing organic modifier (AO-OM) was then introduced into natural montmorillonite (MMt) through a cation-exchange reaction resulting in antioxidant-containing organo-modified clay (AO-OM-MMt). The new antioxidant-containing modified clay, along with other organo-modified clays having a similar organo-modifier but without the reacted antioxidant, were characterised by spectroscopic, thermogravimetric and x-ray diffraction techniques and tested for their thermo-oxidative stability. PA11-based clay nanocomposites samples containing the AO-OM-MMt and the other organo-modified clays, both without and with an added (i.e. not chemically reacted) hindered phenol antioxidant (similar to the one used in the AO-OM) were prepared by melt processing and examined for their processing and long-term thermal-oxidative stability at high temperatures. It was shown that although the new organo-modifier, AO-OM, was also susceptible to the Hoffman elimination reaction, the nanocomposites containing this newly modified clay (PA11/AO-OM-MMt) showed higher melt processing and long-term thermo-oxidative stability, along with excellent clay dispersion and exfoliation, compared to the other PA11-nanocomposites examined here (with and without the conventionally added antioxidant). It is suggested here that the excellent overall performance observed for the PA11/AO-OM-MMt nanocomposites is due to an in-situ partial release of low molecular weight antioxidant species having stabilising functionalities that are capable of acting locally at the interface between the inorganic clay platelets and the polymeric matrix which is a critical area for the onset of degradation processes

Effect of Nanodiamonds on Structure and Durability of Polyethylene Oxide-Based Nanocomposites

Polymer-based nanocomposites containing nanodiamonds (NDs) are attractive multifunctional materials with a growing range of applications. In this work, in the frame of developing completely biocompatible systems, nanocomposites based on polyethylene oxide (PEO) and different amount of NDs have been formulated through melt mixing and fully characterized. In particular, the reinforcement effect of NDs in PEO has been probed through tensile tests, and the rheological response of PEO-based nanocomposites as a function of the nanoparticles amount has been investigated and discussed. The obtained results show that the presence of well-distributed NDs strengthens the mechanical performance of the nanocomposites and brings about an increase of the PEO crystallinity, suggesting a strong adhesion between NDs and polymer matrix. Furthermore, as a result of NDs adding, alterations of the rheological behaviour of neat PEO can be noticed, as NDs are able to significantly influence the long-range dynamics of PEO chains. Besides, accelerated aging tests demonstrate that NDs show a remarkable protective ability against PEO photodegradation, due to their ability to attenuate efficiently UV radiation. The latter opens up new avenues for the use of NDs as multifunctional nanofillers for polymer-based nanocomposites with enhanced photooxidative resistance

Polar Wax as Adhesion Promoter in Polymeric Blend Films for Durable Photovoltaic Encapsulants

Technological developments in the solar photovoltaic field must guarantee the high performance and low deterioration of solar cells in order for solar power plants to be more efficient and competitive. The solar cell needs comprehensive protection offered by a polymeric encapsulant, which improves UV stability, reduces water and moisture absorption, reduces oxygen and vapor permeability and enhances mechanical resistance. Moreover, high transparency and adhesion yields improved the solar panel performance. The current work analyzes polymeric films based on poly(ethylene-co-vinyl acetate) (EVA) and polyolefin (PO) for photovoltaic encapsulant use (the high temperature resistance is improved by adding PO to EVA, as investigated and documented before). To enhance the mechanical resistance and optical properties of the investigated matrices, a crosslinking agent, an adhesion promoter and stabilizing agents have been incorporated in both EVA and EVA/PO systems. The adhesion promoter is a polar wax–silane-free agent; the absence of the silane function allows the integrity of the module to be maintained over time. All samples were characterized through mechanical and rheological analysis, and their long-term UV stability was investigated by accelerated ageing and by FTIR and UV–vis spectroscopy. The obtained results suggest that the presence of a crosslinking agent, an adhesion promoter and stabilizers in EVA/PO-based films allows for the achievement of the required features for the encapsulants, showing mechanical and rheological behavior similar to those of EVA containing the same additives

Natural Compounds as Sustainable Additives for Biopolymers

In the last few decades, the interest towards natural compounds, coming from a natural source and biodegradable, for biopolymers is always increasing because of a public request for the formulation of safe, eco-friendly, and sustainable materials. The main classes of natural compounds for biopolymers are: (i) naturally occurring fillers (nFil), such as nano-/micro- sized layered alumino-silicate: halloysite, bentonite, montmorillonite, hydroxyapatite, calcium carbonate, etc.; (ii) naturally occurring fibers (nFib), such as wood and vegetable fibers; (iii) naturally occurring antioxidant molecules (nAO), such as phenols, polyphenols, vitamins, and carotenoids. However, in this short review, the advantages and drawbacks, considering naturally occurring compounds as safe, eco-friendly, and sustainable additives for biopolymers, have been focused and discussed briefly, even taking into account the requests and needs of different application fields

Effect of different processing techniques and presence of antioxidant on the chitosan film performance

In the last two decades, the naturally occurring polysaccharides have gained great attention because of their potential applications in different sectors, for example, from food to biomedical sectors. Chitosan is a cationic polysaccharide with good transparency, and currently, it has been considered also as suitable material for the formulation film and coating in cultural heritage protection. In this work, the chitosan films (Ch), with and without natural antioxidant such as citric acid (CA), are formulated considering two different processing techniques: (i) conventional solvent casting and (ii) compression molding, that is an unconventional method for this polysaccharide, giving the possibility to formulate films with extended surface and constant thickness. The effects of processing conditions and antioxidant presence on the properties and performance are evaluated by thermo-gravimetric analysis, FTIR and UV-visible spectroscopy, water contact angle measurements and tensile test. Besides, the durability of all investigated Ch and Ch/CA has been evaluated subjecting thin film to UVB exposure and monitoring their structural changes by FTIR analysis in time. All obtained results suggest that the chitosan films can be processed successfully by both solvent casting and compression molding techniques. Further, the CA presence in Ch films has a beneficial effect on the thermal resistance and durability and no negative effect on the transparency and optical properties

Effect of Nanodiamonds on Structure and Durability of Polyethylene Oxide-Based Nanocomposites

Polymer-based nanocomposites containing nanodiamonds (NDs) are attractive multifunctional materials with a growing range of applications. In this work, in the frame of developing completely biocompatible systems, nanocomposites based on polyethylene oxide (PEO) and different amount of NDs have been formulated through melt mixing and fully characterized. In particular, the reinforcement effect of NDs in PEO has been probed through tensile tests, and the rheological response of PEO-based nanocomposites as a function of the nanoparticles amount has been investigated and discussed. The obtained results show that the presence of well-distributed NDs strengthens the mechanical performance of the nanocomposites and brings about an increase of the PEO crystallinity, suggesting a strong adhesion between NDs and polymer matrix. Furthermore, as a result of NDs adding, alterations of the rheological behaviour of neat PEO can be noticed, as NDs are able to significantly influence the long-range dynamics of PEO chains. Besides, accelerated aging tests demonstrate that NDs show a remarkable protective ability against PEO photodegradation, due to their ability to attenuate efficiently UV radiation. The latter opens up new avenues for the use of NDs as multifunctional nanofillers for polymer-based nanocomposites with enhanced photooxidative resistance