Optimized superhydrophobic and self-cleaning nanocomposite surfaces were obtained by spraying surface modified ZnO nanoparticles (NPs) onto PDMS, using octadecylphosphonic acid and octadecanethiol as hydro-phobic modifiers. In this study, it is the first time to our knowledge that surface parameters such as topography, morphology, superhydrophobicity, and self-cleaning are correlated to particle surface distribution and agglomeration parameters obtained by image analysis. The topography, morphology, and wettability of the surfaces were analyzed using atomic force microscopy, scanning electron microscopy, static contact angle (SCA), and contact angle hysteresis measurements. Image analysis was performed using the new enhanced graphical user interface of a previously self-developed Matlab (R) algorithm. Both hydrophobization methodologies increased the NPs' surface coverage and the hierarchical rough structure formation on the substrates, resulting in more homogenous superhydrophobic self-cleaning surfaces. A higher coated fraction and lower degree of interconnected uncoated PDMS paths are correlated to an increase in SCA. The combination of a higher ag-glomerates fraction, lower agglomerate radius, and lower distance between agglomerates obtained for the sur-faces with hydrophobized ZnO-NPs rendered self-cleaning surfaces. The observed correlations increase the understanding of the design and modelling of superhydrophobic self-cleaning PDMS/ZnO nanocomposite sur-faces for use in high voltage outdoor insulators.

The effect of modification of sisal fibre with propionic anhydride and vinyltrimethoxy silane on the microbiological stability of poly(hydroxybutyrate-co-valerate) (PHBV) was investigated. The effect of the coupling agent - PHBV grafted with maleic anhydride (PHBV-g-MA) was also investigated. The best adhesion at the interface was observed for propionylation of sisal fibre, which improved the thermal properties of the composites. Composites with modified sisal fibre were characterized by higher activation energy (155 kJ/mol), which is related to stronger interactions at the matrix-fibre interface. In the microbial growth test, all biocomposites showed a decrease in molecular weight due to enzymatic degradation by Aspergillus niger. The most resistant to microorganisms was the composite containing propionylated sisal fibre. DMTA and TGA also confirmed the highest microbiological stability of the composite with the addition of propionylated sisal fibre, as evidenced by the smallest change in the properties after the microbiological growth test. In contrast, PHBV-g-MA caused significant enzymatic degradation due to the presence of large amorphous regions.

A methodology was developed for qualitative assessment and characterisation of particle lossesfrom nanocomposites during service life. The methodology can be generalised to other systemswhere the material fragments during ageing and can be extended to quantitative analysis. Achamber was constructed for ageing of selected materials, which enabled effective collectionand subsequent analysis of released particles. A combination of scanning and transmissionelectron microscopy and energy dispersive X-ray spectroscopy was found to be suitable forcharacterising particles in terms of size, shape and content. The methodology was tested on acommon nanoclay composite with polypropylene as the matrix. There was no need forphysical/mechanical wear to generate particles, slow flow of air and elevated temperature ledto cracking and fragmentation of the material, and subsequent release of nanocompositeparticles containing embedded or protruding clay. The release of pure clay particles andpolypropylene particles was also detected. Using the methodology, it was observed that evenin ‘mild’ degradation conditions (pure thermo-oxidation with no wear), fillers andnanocomposite particles can be released to the environment, which is an environmental andhealth concern.

This work was done to improve the interfacial adhesion and engineering performance of polyvinyl alcohol/polylactic acid laminate film by altering the polyvinyl alcohol phase surface properties via incorporating microfibrillated cellulose modified by propionylation. Incorporating the modified microfibrillated cellulose into polyvinyl alcohol film improved adhesion between film layers during the laminating process. Improved peel strength and tensile properties confirmed that modified microfibrillated cellulose can produce better bonding between polyvinyl alcohol and polylactic acid via mechanical interlocking and cohesive forces at the film interface. Modified microfibrillated cellulose (3 wt%) increased the peel strength by 40% comparing with the neat polyvinyl alcohol/polylactic acid laminate film.The reduction of both moisture absorption and diffusion rate of the modified microfibrillated cellulose–polyvinyl alcohol/polylactic acid to 20 and 23%, respectively, also indicated that the modified microfibrillated cellulose could inhibit moisture permeation across the film. This was because the modified microfibrillated cellulose is hydrophobic. Furthermore, the addition of modified microfibrillated cellulose also increased the decomposition temperature of the laminate film up to 10% as observed at 20% of remaining weight, while the storage modulus substantially increasing to 72% relative to the neat laminate film.The superior interfacial adhesion between the polylactic acid and modified microfibrillated cellulose–polyvinyl alcohol layers, observed by scanning electron microscopy, confirmed the improved compatibility between the polyvinyl alcohol and polylactic acid phases.

This study presents comparative assessments on hydrophilic and hydrophobic ZnO nanoparticles and their deposition methods on the surface hydrophobicity of silicone rubber (PDMS) and glass substrates. The influence on the surface hydrophobicity and wettability of all the variables regarding the deposition methodologies and the interaction of the nanoparticles with the substrates were within the scope of this study. The different surfaces created by spraying, dipping and drop-pipetting deposition methods were assessed by static contact angle measurements and contact angle hysteresis from advancing and receding angles, as well as by the calculation of the sliding angle and the surface energy parameters. An accurate methodology to determine the contact angle hysteresis was proposed to obtain repetitive and comparative results on all surfaces. All the measurements have been correlated with the morphology and topography of the different surfaces analysed by FE-SE microscopy. The spray-deposition of hydrophobic ZnO nanoparticles on PDMS resulted in super-hydrophobic surfaces, exhibiting hierarchical structures with micro-and nanometer features which, together with the low surface energy, promotes the Cassie-Baxter wetting behavior. This study provides the fundamental approach to select critically the most promising combination in terms of materials and deposition techniques to create silicone-based super-hydrophobic surfaces with potential to be applied in high voltage outdoor insulation applications.

Lignocellulosic biocomposite is a promising biodegradable materials, though improvement of the interfacial adhesion between cellulose fibre and polymer matrix is still challenged. Therefore, this work investigated the effect of propionylation of sisal reinforced fibre in the sisal/polyhydroxybutyrate-co-valerate (PHBV) biocomposite. Propionylation involved esterification substitution of propionic anhydride to hydroxyl group of sisal fibre, where ester group (COOR) of propionylated fibre was successfully observed by Fourier transform Infrared spectroscopy (FTIR). Then mechanical and thermal properties were evaluated and biodegradation characteristics were assessed. The tensile strength and modulus of propionylated sisal/PHBV biocomposite were greater than unmodified sisal/PHBV, which revealed better compatibility at the interface. In addition, propionate moieties of sisal fibre could induce crystalline formation of PHBV, as determined by an increase of crystalline phase. The higher decomposition temperature (Td) and activation energy (Ea) of 155 kJ.mol(-1), determined by thermal gravimetric analyser (TGA), were strong confirmation of good thermal resistance of the propionylated sisal biocomposite. The storage modulus, as characterized by dynamic mechanical thermal analyser (DMTA), also revealed the improvement of stiffness. Bacterial growth tests evaluated the inhibition of bacterial growth on the PHBV biocomposites. It was clear that propionylation of sisal fibre decreased colonization of Staphylococcus aureus (SA) and Escherichia coli (E.coli).

This continuous research within Nordic engineering institutions targets the contexts and possibilities for leadership among engineering education program directors. The IFP-model, developed based on analysis of interviews with program leaders in these institutions, visualizes the program director's informal and formal power. The model is presented as a tool for starting a shared discussion on the complexities of the leadership of engineering program development. The authors liken program development to hunting in teams. Each individual expert in the program is needed, and all experts will need to work and collaborate for the same target. This calls for strategic and long-term thinking of engineering education development. Institutions should support the development of both formal structures as well as informal leadership skills among their program directors, but never fall for the temptation to see the program director as the only actor on the stage.

In this work, different loads (3, 5 and 7 wt%) of pine cone cellulose nanocrystals (CNCs) were added to films of poly(3-hydroxybutyrate)/poly(ε-caprolactone) (PHB/PCL) blends with a composition of 75 wt% PHB and 25 wt% PCL (PHB75/PCL25). The films were obtained after solvent casting followed by melt compounding in an extruder and finally subjected to a thermocompression process. The influence of different CNCs loadings on the mechanical, thermal, optical, wettability and disintegration in controlled compost properties of the PHB75/PCL25 blend was discussed. Field emission scanning electron microscopy (FESEM) revealed the best dispersion of CNCs on the polymeric matrix was at a load of 3 wt%. Over this loading, CNCs aggregates were formed enhancing the films fragilization due to stress concentration phenomena. However, the addition of CNCs improved the optical properties of the PHB75/PCL25 films by increasing their transparency and accelerated the film disintegration in controlled soil conditions. In general, the blend with 3 wt% CNCs offers the best balanced properties in terms of mechanical, thermal, optical and wettability.

The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A statistical design of experiments was applied to study the influence of the addition of sisal (0–10–20–30%wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermo-oxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied to simulate the potential of thermal recovery technologies, such as pyrolysis and controlled combustion, to use these biocomposites after the end of their service life. The mathematical descriptions of both thermo-chemical reactions were helpful in the evaluation of the eventual optimal operational conditions to carry out a suitable energetic valorisation. A minimum of 240°C and 137 kJ/mol of activation energy in inert conditions and 236°C and 118 kJ/mol in oxidative conditions ensured the feasibility of the reactions regardless the composition of the PHBV/sisal biocomposites, which may ease the operability of further energy valorisation with the aim to turn biowaste into new fuels.

The thermal stability and decomposition kinetics of PLA/sisal biocomposites was discussed to evaluate the suitability of their use in energy recovery processes such as pyrolysis and combustion. The influence of the addition of sisal up to 30%wt, the presence of coupling agent, and the atmosphere of operation, i.e. inert or oxidative was discussed by means of multi-rate linear non-isothermal thermogravimetric experiments. All biocomposites showed a mean high heating value of 15 MJ/kg indicating their suitability for energy recovery processes. The thermal requirements of PLA/sisal decomposition were assessed in terms of onset decomposition temperature and apparent activation energy. A minimum of 240 degrees C and 174 kJ mol(-1) in inert environment and 225 degrees C and 190 kJ mol(-1) in oxidative environment ensured the feasibility of the reactions regardless the composition of the PLA/sisal biocomposites. The atmosphere of work lead to a greater amount of residue in case of pyrolysis reactions that would need further treatment whereas an oxidative atmosphere resulted in nearly zero final waste stream. The similar kinetics obtained for all samples regardless the amount of sisal or use of coupling agent eases the operability of energy facilities aimed of turning these biowastes into new fuels.