Particles, Polymers and Biomaterials Technology (PPB)

PPB preserves a long tradition in the field of particle characterization including size and on the determination of other chemical, physical and morphological properties of dispersed materials (eg., micro- and nanoparticles; nanofibres; emulsions/nanoemulsions). Additionally, R&D activities on this topic also include: continuous monitoring techniques for aggregation and particle formation processes; tomographic techniques to monitor multiphase processes (solid/liquid, liquid/liquid); rheological studies (eg., suspensions, hydrogels); emulsion and nanoemulsion formation using ultrasounds/membrane processes; application of nanostructured materials to soil (stabilization/remediation); nanotoxicology in aquatic environments; microplastics characterization and removal from waste waters, etc. At the mechanistic level population balance modelling and computational fluid dynamics (CFD) modelling of the flow in different processes are also areas of interest.

R&D activities on this topic are mostly focused on the synthesis, modification/functionalisation processing, and characterisation of polymers and polymeric/inorganic/composite biomaterials, as well as on their applications in different practical areas.

Specific examples of these activities include: new polymerization/functionalisation techniques (e.g., ATRP, photografting); biomimetic/nanoemulsions-based sol-gel methods; non-conventional nano-structuring and processing methods (e.g., foaming/mixing); synthesis/processing of bio-based polymers; new biodegradable synthetic polymers (eg., polyester-based); new additives/formulations for polymer-based products (eg., paints, coatings, adhesives, textiles, plastics, etc.); stimuli-responsive polymer-based materials/biomaterials (e.g, amide- and ionic liquid-based); screening/testing of biopolymers as substitutes for conventional synthetic polymers, etc.

In addition to most conventional applications (coatings, adhesives, textiles, plastics, separation/purification, water treatment, materials presenting low emissions of volatile organic compounds (VOC), electronics, etc.), special attention has been devoted to the application of these polymer-based particulate or monolithic systems in pharmaceutical applications (medicines, drug delivery, antimicrobial systems), biomedical applications (bioadhesives, biosensors, ophthalmic devices, wound dressings, tissue engineering scaffolds, etc.), or other applications (cosmetic formulations, food ingredients & packaging, nutraceutical delivery, sterilization, crop protection and pesticide delivery, etc.).

The great majority of the R&D activities on this topic aim to develop sustainable processes (e.g., extraction/fractionation, reaction, biocatalysis, fermentation, formulation, etc.) and added-value products intended for a wide range of practical applications, by employing integrated Biorefinery, (Bio)Circular Economy, Atom-Economy, and Green Chemistry/Engineering approaches. Emphasis had been made on the use of forest- or wood/pulp-based raw materials, despite agro-industrial and marine-based raw materials, as well as the wastes, residues and sub-products generated by these activities, have been increasingly integrated into PPB research.

Specific examples of these activities include: fermentation of wood and pulp sludge liquid hydrolysates to produce bioethanol; production of biological products (pigments, proteins, etc.) using microbial cell factories; extraction, separation and purification of a wide range of natural products (antioxidants, essential oils, lipids, colorants, tannins, biopolymers, etc.) and their modification, formulation and valorisation into a variety of applications (pharmaceutical, biomedical, cosmetic, food/nutraceutical, agriculture, papermaking, bio-fuels, bio-solvents, water treatment, others).

R&D activities around this topic are focused either on industrial problems or fundamental research. Close collaborations and partnerships have been established along the years with the national papermaking industry, also including RAIZ - Forest and Paper Research Institute. Specific examples of the R&D activities include: cooking/bleaching processes; flow dynamics of pulp fibre suspensions; flocculation processes (mechanisms/optimization); paper surface characterization and modification, filler flocculation/modification; use of new additives (micro/nanocelluloses) for different applications (e.g., paper products and papermaking process, water treatments); new paper-based materials for specific applications; paper-ink interactions; dimensional stability analysis; etc.

R&D activities within this topic aim to develop safer and more sustainable processing approaches towards new or enhanced products (for a large number of applications). Two of these approaches consider the use of inherently greener, safer, renewable and/or recyclable: i) raw materials, additives, chemical precursors and processing agents (e.g., obtained from abundant and/or renewable sources, or from wastes/residues); and ii) solvents (water/ethanol-based, supercritical carbon dioxide, ionic liquids/deep eutectic solvents, bio-solvents, other). A third approach, which is often combined with the first ones, considers the use of inherently safer, greener, integrated and less energy-intensive processes (e.g., catalytic-, bio-catalytic and biotechnology-based reactions, high pressure and supercritical-based processes, aqueous biphasic separation systems, membrane-based processes, etc.).

Specific examples include: dissolution/extraction/purification/processing of a wide range of natural products (from different types of biomass); fermentation of wood and pulp sludge; use of natural products as precursors, solvents or catalysts in nanoparticle and flocculants production; plasticisation and thermal stabilisation of PVC-based plastic materials; use of supercritical carbon dioxide as a new disinfecting or sterilising agent; emulsification using membrane processes; etc.

A more recent R&D area at PPB deals with the development of new natural and synthetic drugs. Synthetic steroids and hydroxycinnamic acid derivatives are developed as anti-tumour and anti-inflammatory agents, respectively, while natural bioactive (poly)phenols and terpenes are studied in different therapeutic targets (including antimicrobial). Contemporary approaches of medicinal chemistry are currently applied for the development of new synthetic drugs, namely by using rational approaches based on active ligands and target 3D structures, by doing biological evaluation with well-known methods, and by developing novel procedures complemented with molecular modelling.