Laura Sisti

University of Bologna | UNIBO · Department of Civil, Chemical, Environmental and Materials Engineering DICAM

This study presents a multidisciplinary approach for dealing with the environmental problems related to agro‐industrial coffee residues. The exploitation of these residues allows biomolecules to be obtained from renewable sources and enables the preparation of CO2‐neutral biocomposites, with the advantages of reducing fossil depletion, avoiding cli...

As a new generation of green solvents, deep eutectic solvents (DESs) are considered a promising alternative to current harsh organic solvents and find application in many chemical processing methods such as extraction and synthesis. DESs, normally formed by two or more components via various hydrogen bond interactions, offer high potential as mediu...

In this work, the evaluation of the antioxidant activity of natural phenolic compounds is performed and compared to that of a conventional antioxidative agent. Phenolic molecules, extracted from industrial processing coffee residues, are added to a matrix of poly(1,4‐butylene succinate) (PBS). The apparent activation energy (Ea) of the thermo‐oxida...

The depletion of fossil resources and the growing demand for plastic waste reduction has put industries and academic researchers under pressure to develop increasingly sustainable packaging solutions that are both functional and circularly designed. In this review, we provide an overview of the fundamentals and recent advances in biobased packaging...

Food waste valorization, considered as energy and/or chemicals source, via biorefinery or biotechnology, gained great attention in recent years, because of the fast depletion of primary resources, increased waste generation and landfilling worldwide. Coffee by-products for example (i.e. coffee pulp, coffee husks, silver skin, spent coffee, etc.) ha...

The use of degrading enzymes in polymer formulation is a very attractive strategy to manage the end-of-life of plastics. However, high temperatures cause the denaturation of enzymes and the loss of their catalytic activity; therefore, protection strategies are necessary. Once protected, the enzyme needs to be released in appropriate media to exert...

The use of polymer-degrading enzymes in polymer formulation is a very attractive strategy for the life-cycle of plastics. The design of a material able to degrade on-demand could help reach the ambitious targets pursued by recent European policies. Only 32% of the resulting waste from the 50 million tonnes of plastics consumed each year in Europe i...

The use of bioplastic mulch in agriculture has increased dramatically in the last years throughout the world. Nowadays, biodegradable materials for mulching films strive to constitute a reliable and more sustainable alternative to classical materials such as polyethylene (PE). The main challenge is to improve their durability in the soil to meet th...

Commercial hydrolytic enzymes belonging to different subclasses (several lipases, proteinase k, cutinase) were investigated for their ability to degrade different aliphatic polyesters, i.e., poly(butylene succinate) (PBS), poly(butylene succinate-co-adipate) (PBSA), two poly(caprolactone), having two different molecular weights, poly(lactic acid) (...

2,5‐Furandicarboxylic acid (FDCA) is currently considered one of the most relevant bio‐sourced building blocks, representing a fully sustainable competitor for terephthalic acid as well as the main component in green polymers such as poly(ethylene 2,5‐furandicarboxylate) (PEF). The oxidation of biobased 5‐hydroxymethylfurfural (HMF) represents the...

The production of degradable packaging materials is a task that can be no longer postponed. Moreover, high amounts of agricultural wastes are landfilled without any recycling. In this research, the possibility to formulate particulate composites made of biopolymers filled with coffee waste with acceptable physical and mechanical characteristics tha...

Particulate composites based on poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) biopolymers have been formulated. Silver skin (SSK), the by-product derived from the roasting of coffee beans, has been milled to micrometric size and added up to a 30 wt% of loading, without any previous treatment. The dynamic mechanical properties of the co...

When considered by a biorefinery approach, an agroindustrial byproduct such as wheat bran can find a new standing in the field of fabrication of mycelium-based materials. The present work reports on a systematic study on the effect of wheat bran as an upgrading feedstock for the growth and development of fully biobased and biodegradable composites....

Nowadays the issues related to the end of life of traditional plastics are very urgent due to the important pollution problems that plastics have caused. Biodegradable plastics can help to try to mitigate these problems, but even bioplastics need much attention to carefully evaluate the different options for plastic waste disposal. In this Minirevi...

In recent years, the circular economy and sustainability have gained attention in the food industry aimed at recycling food industrial waste and residues. For example, several plant-based materials are nowadays used in packaging and biofuel production. Among them, by-products and waste from coffee processing constitute a largely available, low cost...

In situ intercalative polymerization has been investigated as a strategic way to obtain poly(propylene 2,5-furandicarboxylate) (PPF) and poly(hexamethylene 2,5-furandicarboxylate) (PHF) nanocomposites with different graphene types and amounts. Graphene (G) has been dispersed in surfactant stabilized water suspensions. The loading range in composite...

With the aim to fully exploit the by-products obtained after the industrial extraction of starch from sweet potatoes, a cascading approach was developed to extract high-value molecules, such as proteins and pectins, and to valorize the solid fraction, rich in starch and fibrous components. This fraction was used to prepare new biocomposites designe...

Agro-waste reduction and reuse are among the current main social challenges. In this perspective , the present research was aimed at the complete valorisation of Garganega grape pomace by recovering bioactive phenol extracts and by testing the solid fibre extract residues in composite formulation for packaging applications. The pomace was derived f...

Two winery residues, namely vine shoots (ViSh) and wine pomace (WiPo), were up-cycled as fillers in PHBV-based biocomposites. Answering a biorefinery approach, the impact of a preliminary polyphenols extraction step using an acetone/water mixture on the reinforcing effect of fillers was assessed. Biocomposites (filler content up to 20 wt%) were pre...

Poly(ricinoleic acid) (PRA), coming from the self-polycondensation of ricinoleic acid (RA), which derives from castor oil, is a very interesting polymer because of its intrinsic antimicrobial activity. However, its mechanical properties are insufficient for whatever application, thus copolymerization is required. In this work, two polyesters based...

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Polybutylene succinate (PBS) were processed in melt extrusion by dispersion of organo-modified layered double hydroxide (LDH). Depending on the organic anion interleaved into LDH fillers (L-tyrosine (TYR), L-tryptophan (TRP), L-ascorbate (ASA) and 3-(4-hydroxyphenyl)propionate (HPP)), it was possible to control and tune the properties of the result...

The world is confronted with the depletion of natural resources due to their unsustainable use and the increasing size of populations. In this context, the efficient use of by-products, residues and wastes generated from agro-industrial and food processing opens the perspective for a wide range of benefits. In particular, legume residues are produc...

3-(4-hydroxyphenyl)propionic acid, intercalated in Mg2Al/layered double hydroxide has been used as filler in biopolyesters containing succinate moiety, such as poly(propylene succinate) (PPS), poly(butylene succinate-co-butylene adipate) (PBSA) and poly(butylene succinate) (PBS) with the aim of inducing an effect similar to that of an increment of...

The paper aims at optimising and validating possible routes toward the full valorisation of grape agrowaste to produce bioactive molecules and new materials. Starting from Merlot red pomace, phenol complex mixtures were successfully extracted by using two different approaches. Extracts obtained by solvent-based (SE) technique contained up to 46.9 g...

Particulate composites based on poly(lactic acid) and poly(butylene succinate) biopolymers have been formulated. Silver skin, the by-product derived from the roasting of coffee beans, has been used as a filler up to a 30 wt% of loading. The microstructure, crystallinity, thermal stability, mechanical properties and water absorption of the derived c...

Olive mill wastewater (OMW) is the aqueous waste derived from the production of virgin olive oil. OMW typically contains a wide range of phenol-type molecules, which are natural antioxidants and/or antibacterials. In order to exploit the bioactive molecules and simultaneously decrease the environmental impact of such a food waste stream, OMW has be...

Polybutylene succinate (PBS) nanocomposite materials were prepared using a melt compounding process. The Mg2Al-based PBS nanocomposites, dispersed with inorganic–organic hybrid materials (layered double hydroxides, LDHs), were functionalized with the amino acids L-histidine (HIS) and L-phenylalanine (PHE). The rheological and anti-ultraviolet (anti...

Olive Mill wastewater (OMW) is a food waste stream resulting from the production of virgin olive oil, rich in valuable natural biocompounds, such as vanillic acid, ferulic acid, protocatechuic acid, etc. In order to decrease its environmental impact and to exploit the antioxidant properties of its phenol-type molecules, OMW was intercalated into Zn...

The development of high-performance materials made from natural resources is increasing worldwide. Within this framework, natural fiber reinforced polymeric composites now experience great expansion and applications in many fields, ranging from the automotive to the construction sector. The great challenge in producing composites containing natural...

Hybridization of layered double hydroxide (LDH) platelets of Zn2Al cation intra-sheet composition was performed with L-tyrosine (TYR), L-tryptophan (TRP) and 3-(4-hydroxyphenyl) propionic (HPP) acid, and the hybrid LDH materials were characterized by the means of conventional techniques as X-ray diffraction and thermal analysis to address their san...

The aim of this work is to elucidate the reinforcing potential of enzymatically treated curaua fibers in biodegradable poly(butylene succinate) (PBS)-based composites. The effect of two different enzymes, i.e. cellulase and pectinase, was evaluated. Untreated and enzymatically treated curaua fibers were characterized in terms of thermal stability (...

Particulate composites with polylactide (PLA) as a matrix and wastes deriving from the wine production have been formulated at different compositions. The microstructure and the mechanical properties of the composites, as well as the thermal stability and water uptake have been evaluated. The results showed that the wine waste residue does not comp...

Bio-based polyamide 11 (PA11)-graphene nanocomposites with different filler concentrations (0.25, 0.5, 0.75, 1.5 and 3 wt%) were prepared by In Situ polymerization starting from a water dispersed suspension of graphene nanoplatelets. The effects of the incorporation of the filler were studied in terms of molecular, morphological, thermal and dynami...

New fully biobased polyether/esters have been synthesized by a one-pot polymerization reaction of ricinoleic acid (RA), vanillic acid (VA) and ethylene carbonate (EC). In particular, EC selectively reacts with the phenolic group of VA to obtain in-situ 4-(2-hydroxyethoxy)-3-methoxybenzoate (EV), suitable for subsequent copolymerization with RA. The...

Composites formulated with an epoxy matrix, kenaf fibers, and the residuals of the wine industry are investigated at different compositions. The microstructure and the mechanical properties of the composites have been studied, as well as their moisture uptake. A proper mix design of the composite can allow the waste inclusion as filler either incre...

Nanocomposites based on poly(butylene succinate) (PBS) and hydrotalcite-type anionic clays (HTs) organo-modified with biomolecules characterized by antibacterial and/or antioxidant activity, such as L-ascorbic acid (ASA), phloretic acid (HPP), L-tyrosine (TYR) and L-tryptophan (TRP), have been prepared by in situ polymerization. From XRD analysis a...

Poly(cyclohexane-1,4-dimethylene cyclohexane-1,4-dicarboxylate) has been prepared by solid-state polymerization using 1,4-cyclohexanedicarboxylic acid or its di-methylester and 1,4-cyclohexanedimethanol as monomers. The process consists in a first step in which a prepolymer with high crystallinity is prepared by melt polycondensation and then submi...

Rice endosperm, an industrial by-product containing starch as the main component, has been used for the production of novel biocomposites, based on poly(butylene succinate) (PBS). The composites were prepared by melt-mixing, using original or enzymatically-treated rice endosperm. This enzymatic treatment enables the extraction of some high value mo...

In order to address the need for more efficient technologies for carbon capture applications, a novel type of nanocellulose based hybrid membrane has been successfully prepared by blending the commercial Polyvinylamine solution Lupamin® 9095 (BASF) with Nano Fibrillated Cellulose (NFC) to improve its mechanical and separation capabilities. Self-sta...

The vast and ever-growing amount of agricultural and food wastes has become a major concern throughout the whole world. Therefore, strategies for their processing and value-added reuse are needed to enable a sustainable utilization of feedstocks and reduce the environmental burden. By-products of potato, tomato, cereals and olive arise in significa...

3-(4-hydroxyphenyl)propionic acid (HPPA), a biobased hydroxy acid, has been used as organic modifier in Layered double hydroxides (LDHs) based on ZnAl and MgAl cations. PBS bionanocomposites have been prepared via in situ polymerization (with both types of clays) and melt blending (just with ZnAl-HPPA) obtaining completely green materials, potentia...

The invention relates to layered double hydroxides organo-modified by 3-(4-hydroxyphenyl)propionic acid (HPPA), by 2-(4-hydroxyphenyl)ethylsulfonic acid or by a hydroxyphenylpropenoic acid, and to composite polymer materials comprising same. The composite materials are advantageously made of biosourced polymers such as poly(butylene succinate). The...

The retting process, carried out with warm inoculated water, has been evaluated as a potential method to modify the structure of fibers in order to prepare polymeric biocomposites. The efficiency of the method was tested by analyzing the final performances of the produced composites, prepared with reinforcing hemp fibers (Cannabis sativa L.) disper...

Poly(butylene succinate) PBS is a biodegradable synthetic aliphatic polyester whose properties are often favorably compared to LDPE or PP. It is one of the newest biopolymers, currently produced by combining succinic acid and 1,4- butanediol, both either petrol- or bio-based. The market for this biopolymer is still small, limited by capacity and pr...

Given the increasing relevance of poly(butylene succinate) (PBS) and poly(L-lactide) (PLLA) as bio-based thermoplastics, and the need to improve the properties of such polymers, a novel multicomponent reinforcing system was devised. Nanofibrous electrospun mats of PLLA containing graphene were incorporated into the PBS matrix via the conventional t...

Bionanocomposites based on poly(butylene succinate) and a novel organo-modified layered double hydroxide have been prepared by in situ polymerization. In order to enhance the compatibilization of the inorganic filler with the polymer matrix, an oligomer of PBS was intercalated between the layers of the clay. Composites with different percentages of...

Biocomposites based on poly(butylene succinate) (PBS) and curaua fibers have been produced by compression molding, and investigated as a function of fiber length and amount. Mechanical tests, water uptake and morphology studies were carried out in order to assess the composite features according to the characteristics of the reinforcing agents. It...

A sodium montmorillonite, Dellite HPS, was modified with ionic liquids based on phosphonium salts, such as octadecyltriphenylphosphonium tetrafluoroborate and octadecyltriphenylphosphonium bromide. Thanks to their high thermal stability, these salts can be used during in situ polymerization, a method that favors the achievement of a good dispersion...

Novel bio-based and biodegradable electrospun membranes, containing bactericidal ricinoleic acid (RA) units either by copolymerization with butylene succinate (BS) units or by blending PRA and PBS homopolymers, are characterized in their chemical, thermal, mechanical and surface properties. In the blends E. coli and S. aureus mortality rate increas...

A series of layered double hydroxides interleaved with surfactant using saturated alkyl chain carboxylate anions CH3(CH2)(m)COOH, even number m between 6 (C8) and 16 (C18), obtained by coprecipitation method was dispersed by melt polymer extrusion into polypropylene (PP), poly(butylene)succinate (PBS) and polydimethylsiloxane (PDMS). The hybrid LDH...

A series of poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate) (PCCD) samples, characterized by different cis/trans ratio of the 1,4-cyclohexanedicarbonyl units, and a PCCD ionomer, containing 3 mol% of ionic terminal groups, were exposed to accelerated UV in order to study the molecular modifications occurring during the ageing period...

This work aims at preparing new castor oil-derived polyesters with antibacterial activity. Ricinoleic acid and 10-undecenoic acid, derived from castor oil, were successfully used for this purpose. Firstly, an unsaturated homopolymer, derived from the self-polycondensation of ricinoleic acid, and its copolymers with poly(butylene succinate) were syn...

A series of poly(butylene succinate) (PBS) containing organo-modified layered double hydroxide (LDH) are prepared by melt compounding and by in situ polymerization of succinic ester and 1,4-butanediol. Various LDHs intercalated with renewable organic anions are used. More specifically, lauryl sulfate, stearate, succinate, adipate, sebacate, citrate...

Biocomposites based on a polymer with good biodegradability, poly(butylene succinate) (PBS), and reinforced with different lignocellulosic fibers (coconut, sugarcane bagasse, curaua, sisal) were prepared through the traditional thermo-pressed molding technique. The fibers were characterized in terms of chemical composition, thermal stability (TGA),...

In the field of aliphatic polyesters there is a great interest in building novel macromolecular structures that may effectively feature the requiredproperties for specific applications. For this reason, it is extremely important to understand the correlations between chemical structure and final performance. Monomers based on the 1,4-cyclohexylene...

The application of an electric field has been shown to positively influence the impregnation of the resin monomers currently used in dentin bonding systems during hybrid layer formation. This study presents an experimental characterization of the electrical properties of these monomers with the aim of both correlating them to their chemical structu...

Surface coatings of pretreated poly(fluoroethylene propylene) (FEP) films by UV-induced graft copolymerization with 2-hydroxyethyl methacrylate (HEMA) and an antimicrobial agent, 3-hexadecyl-1-vinylimidazolium bromide (VIB), have been carried out. Surface chemical and morphological modifications were investigated with spectroscopic analysis using a...

Anatase-structured TiO2 films were deposited on a commercial fluorinated polymer (FEP) with a treated surface, by means of a sol–gel dip-coating technique. Two different curing temperatures were investigated and the film microstructures were characterized by X-ray diffraction, atomic force microscopy and scanning electron microscopy analyses. The p...

Composites based on PBS and lignocellulosic fibers (coconut, sugarcane bagasse, sisal and curauá) were prepared via thermo-pressing. The effects of the lignocellulosic fibers on the mechanical and thermal properties of the composites were investigated by Izod impact tests, flexural tests and thermogravimetric analysis (TGA). The morphology of the s...

The synthesis of poly(butylene terephthalate) (PBT) nanocomposites by in situ polymerisation method using an organo-modified layered doubled hydroxide is described. 4-Sulfobenzoic acid potassium salt, sodium dodecyl sulfate and dimethyl 5-sulfo isophthalate sodium salt were used as intercalating compounds to improve clay exfoliation. The thermal an...

Poly(butylene terephthalate) (PBT) and poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate) (PCCD) ionomers containing terminal ionic units, derived from a novel sodiosulfonate epoxy molecule, were synthesised using an end capping technique in solution. The sulfonated epoxide has the fundamental feature of selectively reacting with the p...

Titanium-based catalysts for poly(alkylene terephthalate) synthesis have been known for many years. Up to now, organotitanate compounds are used as catalysts on an industrial scale only for the synthesis of poly(butylene terephthalate) (PBT), poly(trimethylene terephthalate) (PTT), and related copolyesters; for poly(ethylene terephthalate) (PET), s...

Poly(propylene terephthalate) (PPT) was subjected to aging at high temperatures (150–190°C) in air and some mechanical (impact strength), physical (weight loss), and electrical (dc conductivity and ac electrical strength) properties were determined as a function of aging time and temperature. Some chemical–physical characteristics (such as the aver...

Crystallization kinetics and melting behaviour of poly(propylene terephthalate) (PPT) were investigated by means of differential scanning calorimetry and hot-stage optical microscopy. Isothermal crystallization kinetics was analysed according to the Avrami treatment. The effects of temperature and duration of melting on the overall rate of isotherm...

Reactive blending with cyclic anhydrides in the melt is a promising process to modify the chemical structure of bisphenol A polycarbonate (PC) by insertion of ester moieties leading to consistent changes in the chemical and physical properties of PC. In particular, by the reaction with succinic anhydride it is possible to insert aliphatic moieties...

Poly(propylene terephthalate) (PPT) samples with different carboxyl terminal groups content were synthesized in bulk and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers under investigation show a good thermal st...

The hydrolysis of sulfonated poly(butylene terephthalate) copolymers was studied. Sulfonated poly(butylene terephthalate) copolymers, referred to as PBT-ionomers (PBTIs), were shown to hydrolyze faster than poly(butylene terephthalate) (PBT). An experiment designed to isolate the effect of the sulfonated isophthalate (SIP) moieties on hydrolysis ra...

Direct current (dc) and alternating current (ac) electrical behavior of a laboratory-synthesized semicrystalline poly(propylene terephthalate) is investigated. The dc charging/discharging currents and electrical conductivity are studied as a function of temperature and time of applied voltage. The conduction mechanisms are pointed out and related t...

A new route to poly(alkylene terephthalate)s by melt reaction of dimethyl terephthalate (DMT) with cyclic aliphatic carbonates such as ethylene carbonate and propylene carbonate is described. Poly(butylene carbonate) was used instead of the cyclic monomer for the synthesis of poly(butylene terephthalate). The polymers prepared by this alternative w...

The thermal and electrical properties of poly(propylene terephthalate) samples with different carboxyl terminal groups content are investigated. The thermal behavior is studied through the rate of crystallization. As regards the electrical properties, dc conductivity and low-frequency relaxation processes are studied as a function of temperature. A...