Organic phase change materials (PCMs) are promising for sustainable energy due to their high storage capacity, broad temperature control, and minimal volume change during phase transitions. However, their application is limited by low thermal conductivity and high leakage caused by volume instability. To address these issues, a shape-stabilizing approach using a nature-based and porous matrix of cellulose from recyclable resources, is proposed. In this study, a cellulose hydrogel-based composite was used as a support for encapsulating polyethylene glycol (PEG 2000) PCM, creating a phase change composite (PCC). Cellulose was extracted from waste newspaper (WP) through alkaline and peroxide treatments, achieving 16.5% efficiency and 78% purity. The cellulose was then used to synthesize different three-dimensional (3D) hydrogel networks with citric acid (CA) as the cross-linking agent. Carbon monofilaments (CFs) were incorporated into the hydrogels to enhance stability, reduce leakage, and improve thermal properties. The thermophysical and morphological characterization of the prepared system revealed that cellulose-based hydrogels were formed through esterification between cellulose hydroxyl groups and CA carboxyl groups. The leakage rate of the (cell-4/CF/PEG) PCC was measured as 4.25 wt% after 5 heating–cooling cycles. The latent heat of melting was similar to pure PEG 2000, with an energy storage capacity increase of 25%. Furthermore, the addition of CFs improved thermal conductivity (k) by 80% and achieved an enthalpy efficiency of 90%. The thermal diffusivity (α), specific heat capacity (C_p), and effective thermal conductivity (k_eff) of the (cell-4/CF/PEG) PCC were recorded as 8.2 × 10⁻⁹ m² s⁻¹, 5400 J kg⁻¹ °C⁻¹, and 0.027 W m⁻¹ °C⁻¹, respectively.

This work looks at the effects of a varying concentration, soak time, pH and temperature on the sorption of tetraammineplatinum(II) chloride (Pt-Ammine) in Nafion-117 films in the context of the electroless plating of ionic polymer–metal composites (IPMCs). Sorption is characterised by atomic absorption spectroscopy. A definitive screening design carried out determined all four factors to be significant for further analysis using response surface modelling. A duplicated central composite design (CCD) was utilised to characterise how the four factors affect the sorption amount and efficiency. Regression models for both responses were of poor fit. Nevertheless, key insights were obtained on the effects of the process parameters on sorption behaviour. The results indicate that above 0.5 g/L Pt-Ammine sorption, the platinisation of 10 × 50 mm IPMC samples through sodium borohydride reduction becomes redundant by the surface resistance metric. IPMCs with surface resistance values of approximately 2.5 Ω/square were obtained through only one round of chemical reduction. Varying surface morphologies and electrode thicknesses were analysed under a scanning electron microscope. The CCD parameter settings were validated. Recommended settings for optimised Pt-Ammine sorption in 10 × 50 mm Nafion-117 films were identified as follows: 1.0 g/L Pt-Ammine concentration, 24 h soak time, pH of 3 and temperature of 20 °C.

A potential route to reducing material complexity in flexible packaging is to improve the oxygen barrier of polyethylene (PE)-based films. This study investigated the influence of ethylene-glycidyl-methacrylate copolymer (EGMA) on the structure and properties of low-density PE (LDPE) composites containing montmorillonite (MMT). Eight formulations containing, 0, 3,5 or 7 wt.%, with or without 10 wt.% EGMA, were produced via melt compounding. Microstructural analysis, density, thermal behaviour, surface wettability, tensile properties and oxygen permeation were evaluated. EGMA reduced the volume fraction of large MMT agglomerates by approximately 52-73% though localised clay-rich regions persisted. Oxygen barrier performance varied in a non-monotonical fashion with respect to formulation. LDPE containing a 5 wt.% MMT loading without the inclusion of EGMA compatibiliser exhibited the lowest permeation value, displaying a 25.1% reduction compared to neat LDPE. Within the EGMA-containing formulations, the best barrier performance was shown for a 3 wt.% loading, noting a 12% reduction compared to neat LDPE. There was no substantial impact on the tensile strength of composite samples regardless of loading level though higher MMT loadings generally increased modulus while reducing elongation. All measured densities remained below 0.97 cm3 in line with RecyClass guidelines. These findings show that EGMA improves large-scale MMT dispersion but does not consistently enhance barrier performance with the uncompatibilised 5 wt.% MMT formulation showing the most favourable combination of oxygen barrier and retained tensile properties.