Water-based ink formulations containing wax, surfactant, and defoamer additives were prepared and printed on polyethylene film substrates. Standard test methods for adhesion, rub resistance, and gloss were done on the printed polyethylene films. Quantitative methods for the assessment and evaluation of the three print properties were developed. Image analyses were done to quantify adhesion and rub resistance. Quantitative measurement was done to quantify gloss. Data were analyzed using mixture design modelling and optimization. Modelling results show that adhesion and gloss are described by special cubic model equations, while rub resistance is described by a linear model equation. Contour plots and 3D surface graphs were generated showing the response surfaces of the print properties. The effects of varying the mass fractions of wax, surfactant, and defoamer on adhesion, rub resistance, and gloss were determined. It was found that increasing wax increases rub resistance, while increasing surfactant increases gloss, and increasing defoamer increases adhesion. There is dependency found between the mass fraction of wax, surfactant and defoamer with respect to the rub resistance, adhesion and gloss. Multi-objective optimization revealed that optimum adhesion, rub resistance, and gloss is obtained by a formulation containing equal mass fractions of wax and surfactant but no defoamer.

Physically crosslinked superabsorbent hydrogels based on NaCMC, HPC, and NaAlg were developed to address the effects of water shortage to crop farming and to regulate fertilizer usage. An optimized synthesis was performed using ten different blends. The blend with a NaCMC/HPC/NaAlg ratio of 0.29/0.42/0.29 was found to exhibit the most favorable results, accommodating 1585% moisture and 8.38% fertilizer on a dry basis. Scanning electron microscope images of this blend manifested microporous structures, responsible for its superabsorbent properties. It was found out that applying the hydrogel at 5% loading to silt soil decreases fertilizer runoff by 28% and increases field capacity to 55%. Moreover, phytotoxicity studies showed that the optimum hydrogel blend exhibits no phytotoxic properties to pechay (Brassica rapa subsp. chinensis), lettuce eton (Lactuca sativa), and spinach (Spinacia oleracea), proving its applicability to agriculture.

A solvent and non-solvent selection method for the chemical recycling through selective dissolution and precipitation of multi-component waste metallized film wrapper is studied to recover Polyethylene (PE), Polypropylene (PP), and the metal film separately. Pre-selection of solvent for dissolution and non-solvent for precipitation is based on the similarity and compatibility of polymer and solvent molecules measured in terms of solubility parameter and calculated using group contribution approach through Hoftyzer and Van Krevelen method. Toxicity, cost, and availability of the solvent are also considered on the selection. A Hansen sphere model is developed for the prediction of polymer solubility in which p-cymene, a low-cost and naturally derived solvent is chosen as solvent and acetone as non-solvent. PE was first recovered through dissolution at a given temperature, followed by precipitation. PP which remained undissolved together with the metal film was extracted through the same technique but with different dissolution temperature. FTIR spectra of the recovered polymers showed similarity compared to virgin PE and PP films. The melting point of the recovered PE and PP using p-cymene determined in the DSC curves were 107.37 °C and 164.55 °C, respectively. Furthermore, the simplicity of the process, high recovery yield obtained, and the application of p-cymene would make the recycling economical and environment-friendly.

Providing enough water in farming has become a challenge in the Philippines due to insufficient irrigation and escalating drought conditions, thereby decreasing agricultural productivity. The impact of this problem can be lessened through efficient water usage: by reducing water wastage in runoff or evaporation and improving soil water retention. Hydrogels can be used for this purpose due to their water absorption capabilities. In this study, a novel, biodegradable agricultural hydrogel was developed from κ-carrageenan, sodium alginate and carboxymethyl cellulose, crosslinked with Ca²⁺ and K⁺ ions. Scanning electron microscopy analysis confirmed the successful crosslinking while swelling tests revealed them as superabsorbent hydrogels, with maximum absorption reaching 2000%. Soil amended with 2% (w/w) hydrogel showed reduced water-depletion rate and improved field capacity by a maximum of 17.6% and 17.4%, respectively. Fertilizer release test also showed the potential of these hydrogels as fertilizer carriers.

Physically cross-linked hydroxyethyl cellulose (HEC) hydrogels of different concentrations are synthesized at room temperature, and the hydrogel films are evaluated for its antimicrobial and exudate absorption properties. Results showed that all the hydrogels inherently possess antimicrobial property for all the HEC concentrations tested. The maximum water uptake is determined to be 173.8% for the 13.75% HEC hydrogel. At the same HEC concentration, the hydrogel absorbed the largest amount of exudate. The rate of diffusion in the longitudinal direction is observed to be higher, but the exudate was observed to travel generally farther in the radial direction. The diffusion coefficient model reported by Kipcak, et al. in 2014 was observed to be valid and applicable for the HEC hydrogels. Lastly, scanning electron microscopy showed the microstructure of the fibers and pores of the hydrogels.

Natural fiber reinforced polymer (NFRP) composites have been a focus of various research projects because of their advantages compared to traditional fiber reinforced plastics. In this study, Anahaw (Saribus rotundifolius) was used as fiber source because it is abundant in the Philippines. The fibers were treated by immersing in a sodium alginate solution and then in a calcium chloride solution. The treated fibers were used to reinforce the orthophthalic unsaturated polyester. Mechanical properties were tested using a universal testing machine (UTM) and the fracture surfaces were characterized using a scanning electron microscope (SEM). Sodium alginate treatment resulted in higher tensile and flexural strengths of the composites as compared to those reinforced with untreated fibers. On the other hand, the sodium alginate treatment was not able to show any improvement on the wet mechanical properties of the material. The increase in fiber load was also found to increase the stiffness of the composites. The measured stiffness and modulus of the treated Anahaw fiber-reinforced composite was found to be comparable to those of commercially available particle boards and fiber boards. Key words: Natural fiber reinforced polymer (NFRP), composite, sodium alginate, anahaw, polymer.