Developing an Effective and Durable Film for Marine Fouling Prevention from PDMS/SiO2 and PDMS/PU with SiO2 Composites

Polymer film coating with a highly hydrophobic surface property is a practical approach to prevent fouling of any structures in the marine environment without affecting marine microorganisms. The preparation of a polymer coating, from a simple and easy method of solution blending of hydrophobic polydimethylsiloxane elastomer and hydrophilic polyurethane with SiO2, was carried out in this study, with the aim of improving characteristics, and the coating demonstrated economic feasibility for antifouling application. Incorporation of SiO2 particles into PDMS and PDMS/PU polymer film improved mechanical properties of the film and the support fabrication of micropatterns by means of a soft lithography process. Observations from field emission scanning electron microscope (FESEM) of the PDMS/SiO2 composite film revealed a homogeneous morphology and even dispersion of the SiO2 disperse phase between 1–5 wt.%. Moreover, the PDMS film with 3 wt.% loading of SiO2 considerably increased WCA to 115.7° ± 2.5° and improved mechanical properties by increasing Young’s modulus by 128%, compared with neat PDMS film. Additionally, bonding strength between barnacles and the PDMS film with 3 wt.% of SiO2 loading was 0.16 MPa, which was much lower than the bonding strength between barnacles and the reference carbon steel of 1.16 MPa. When compared to the previous study using PDMS/PU blend (95:5), the count of barnacles of PDMS with 3 wt.% SiO2 loading was lower by 77% in the two-week field tests and up to 97% in the eight-week field tests. Subsequently, when PDMS with 3 wt.% SiO2 was further blended with PU, and the surface modified by the soft lithography process, it was found that PDMS/PU (95:5) with 3 wt.% SiO2 composite film with micropatterns increased WCA to 122.1° ± 2.9° and OCA 90.8 ± 3.6°, suggesting that the PDMS/PU (95:5) with 3 wt.% SiO2 composite film with surface modified by the soft lithography process could be employed for antifouling application

Material Characterisation Thermal, crystallization, and rheological characteristics of poly(trimethylene terephthalate)/poly(butylene terephthalate) blends

Abstract Blends of poly(trimethylene terephthalate) (PTT) and poly(butylene terephthalate) (PBT) were miscible in all of the blend compositions studied, as evidenced by an observed single and composition-dependent glass transition temperature for each blend composition. The variation of the glass transition temperature with the blend composition was well predicted by the Gordon-Taylor equation, with fitting parameter being ca. 6.9. The cold crystallization (peak) temperature was found to increase, while the melt crystallization (peak) temperature was found to decrease, with increasing PTT content. The subsequent melting behavior for these blends (after cold crystallization) showed the melting point depression behavior, in that the melting (peak) temperature for each component was lowered with increasing content of the other component. During crystallization, the pure components crystallized simultaneously to form their own crystals. The blend having 60 percent by weight of PTT showed the lowest apparent degree of crystallinity. The steady shear viscosities for the pure components and the blends showed slight decrease with increasing shear rate (within the shear rate range of 0.25-25 s Ϫ1 ), with those of the blends lying in between those of the pure components

Simple Preparation of Polydimethylsiloxane and Polyurethane Blend Film for Marine Antibiofouling Application

A key way to prevent undesirable fouling of any structure in the marine environment, without harming any microorganisms, is to use a polymer film with high hydrophobicity. The polymer film, which was simply prepared from a blend of hydrophobic polydimethylsiloxane elastomer and hydrophilic polyurethane, showed improved properties and economic viability for antifouling film for the marine industry. The field emission scanning electron microscope and energy dispersive X-ray spectrometer (FESEM and EDX) results from the polymer blend suggested a homogenous morphology and good distribution of the polyurethane disperse phase. The PDMS:PU blend (95:5) film gave a water contact angle of 103.4° ± 3.8° and the PDMS film gave a water contact angle of 109.5° ± 4.2°. Moreover, the PDMS:PU blend (95:5) film could also be modified with surface patterning by using soft lithography process to further increase the hydrophobicity. It was found that PDMS:PU blend (95:5) film with micro patterning from soft lithography process increased the contact angle to 128.8° ± 1.6°. The results from a field test in the Gulf of Thailand illustrated that the bonding strength between the barnacles and the PDMS:PU blend (95:5) film (0.07 MPa) were lower than the bonding strength between the barnacles and the carbon steel (1.16 MPa). The barnacles on the PDMS:PU blend (95:5) film were more easily removed from the surface. This indicated that the PDMS:PU blend (95:5) exhibited excellent antifouling properties and the results indicated that the PDMS:PU blend (95:5) film with micro patterning surface could be employed for antifouling application

Recycling Waste Nonmetallic Printed Circuit Boards for Polyvinyl Chloride Composites

To reduce environmental threats, such as land filling, incineration and soil pollution, which are associated with the improper waste management of waste printed circuit boards, the utilization of NMPCBs from waste PCBs as a filler in composites was pursued. Untreated and treated NMPCBs in varying ratios, 10–30 wt.%, were blended with PVC to produce NMPCB/PVC composites, using the melt-mixing method via an internal mixer, in order to solve the remaining NMPCB waste problem after the valuable metals in PCBs were recovered. The incorporation of the NMPCB with PVC resulted in an increase in the tensile modulus and the thermal stability of the resulting composites. Scanning electron microscopy (SEM) results indicated improved interfacial adhesion between the treated NMPCB and the PVC matrix. The FTIR results of the NMPCB treated with 3-glycidyloxypropyltrimethoxysilane (GPTMS) revealed the formation of Si-O-Si bonds. The densities of the composites were found to increase with an increase in the content of the treated NMPCB, and compatibility improved. The tensile properties of the treated NMPCB/PVC composites were higher than those of the untreated NMPCB/PVC composites, suggesting improved compatibility between the treated NMPCB and PVC. The PVC composite with 10 wt.% of the treated NMPCB showed the optimum tensile properties. It was observed that the tensile modulus of the treated NMPCB/PVC composite increased by 47.65% when compared to that of the neat PVC. The maximum thermal degradation temperature was 27 °C higher than that of the neat PVC. Dynamic mechanical analysis results also support the improved interfacial adhesion as a result of the improvement in the storage modulus at the glassy region, and the loss factor (tan δ) peak shifted to a higher temperature range than that of the PVC and the untreated NMPCB/PVC composite. These studies reveal that the NMPCB was successfully modified with 1 wt.% of GPTMS, which promoted the dispersion and interfacial adhesion in the PVC matrix, resulting in better tensile properties and better thermal stability of the PVC composite

Investigation of Mechanical and Rheological Properties of Poly (trimethylene terephthalate) (PTT)/Polyethylene Blend Using Carboxylate and Ionomer as Compatibilizers

Poly (trimethylene terephthalate) (PTT) is a linear aromatic polyester with good strength and stiffness, good surface appearance, low shrinkage and war page, and good dimensional stability. However, it has low impact strength which is a problem in automotive application. Thus, modification of PTT with the other polymer or polymer blending is a one way to develop a new material with excellence properties. In this study, PTT/High Density Polyethylene (HDPE) blends and PTT/Linear Low Density Polyethylene (LLDPE) blends with and without compatibilizers base on maleic anhydride grafted HDPE (MAH-g-HDPE) and ethylene-methacrylic acid neutralized sodium metal (Na-EMAA) were prepared by a twin-screw extruder. The blended samples with different ratios of polymers and compatibilizers were characterized on mechanical and rheological properties. Moreover, the phase morphology and dispersion size were studied by using SEM to give better understanding of the compatibility of the blends

Layer-by-Layer (LbL) Surface Augmented Modification of Poly(Styrene/Divinylbenzene)High Internal Phase Emulsion for Carbon Dioxide Capture

In this study, we used amines electrolyte solution with layer-by-layer (LbL) technique to modify and increase the CO2 adsorption capacity of highly porous polymer from high internal phase emulsion template polymer. This perspective presents the extraordinary versatility of emulsion templating polymerization, which has emerged with the growing numbers of HIPE systems and modification. In this study, we used polyHIPE prepared from styrene (S) and divinylbenzene (DVB) with varying ratios; 80:20, 20:80, and 0:100 to improve the surface area, thermal properties, and mechanical properties of the materials. Furthermore, the surface of the polyHIPE was modified by LbL technique to increase the adsorption efficiency. This technique consisted of two main layers, the primary layer of poly(diallyldimethylammonium chloride) (PDADMAC) and polystyrene sulfonate (PSS) and the secondary layer, which was the CO2 adsorbing layer, of polyethylene imine (PEI) or tetraethylene pentamine (TEPA). Poly(S/DVB)HIPE modified by PEI terminated as the secondary coating showed the highest CO2 adsorption capacity, with up to 42% (from 0.71 to 1.01 mmol/g). The amine-multilayered modified material still possessed an open cell structure, since the solution did not block the pore structure of the poly(S/DVB)HIPE and was suitable for being used as an adsorbent in adsorption technology