The thermal behaviour and isothermal crystallisation of cyclic poly(butylene terephthalate)and its blends

This thesis concerns the thermal behaviour and isothermal crystallisation kinetics study of cyclic polyesters and its blends, in particular cyclic poly (butylene terephthalate) (c-PBT). The production of c-PBT is interesting; in fact it is different from production of conventional linear PBT since c-PBT is produced by in situ polymerisation of cyclic butylene terephthalate oligomers (CBT) in the presence of suitable initiators or catalysts. These relatively novel materials, i.e. CBT offer many advantages in properties and the most unusual and useful is that they can be processed at low viscosity (water like) and exhibit rapid crystallisation. The thermal behaviour and isothermal crystallisation kinetics of CBT and c-PBT were analysed. The most significant achievement of this project is blending where blends of c-PBT and styrene maleimide (SMI) were prepared by simultaneous in situ polymerisation and melt blending of solid dispersion CBT/SMI powder. This is unique and novel and the results show consistency and signs of miscibility although there are no external forces applied during the melt blending. It was found that the presence of 30 wt % and above of SMI impeded the crystallisation of c-PBT. This suggests that miscibility occurred. The miscibility of these c-PBT/SMI blends was support with the presence of a single composition-dependent glass transition temperature and negative Flory-Huggins interaction parameter. Studies on crystallisation kinetics of c-PBT were also done by Avrami analysis and using the Hoffman-Lauritzen theory. Previously there have been very limited studies of the crystallisation kinetics of PBT produced from its oligomer. Further work on crystallisation of c-PBT/SMI blends was also performed

Thermal, dynamic mechanical, mechanical and flammability properties of halloysite nanotubes filled polyamide 11 nanocomposites

The effects of various filler contents on the thermal, dynamic mechanical, mechanical, as well as flammability properties of halloysite nanotubes (HNTs) filler and polyamide 11 (PA 11) matrixes are investigated in this research. The nanocomposites were made out of 100 phr of PA 11 and three distinct HNTs loadings of 2, 4, and 6 phr each. PA 11 nanocomposites without HNTs filler was used as the reference sample. To melt-compound the nanocomposites, a twin-screw extruder was used, and the specimen for testing was then injected using an injection mold. SEM, TGA, DSC, FTIR, DMA, tensile, flexural, impact, and UL-94 flammability tests were conducted on the nanocomposites. Incorporation of 4 phr HNTs into the nanocomposites resulted in the highest tensile and flexural strength. Maximum improvement in the DMA, Young’s and flexural modulus was achieved at 6 phr HNTs content. The elongation at break and TGA resulted the highest increase at 2 phr HNTs content. However, the impact strength decreased with increasing HNTs content. Scanning electron microscopy revealed the ductility of the nanocomposites with increased HNTs content up to 4 phr. The DSC showed a steady increase in melting temperature (Tm) as HNTs content increased up to 4 phr, while the crystallization temperature (Tc) remained unchanged. TGA of PA 11/HNTs nanocomposites showed high thermal stability at 2 phr HNTs content. However, on further addition of HNTs up to 6 phr, thermal stability of the nanocomposites decreased due to the excess amount of HNTs. All the nanocomposites passed the horizontal and vertical UL-94 test with HB and V-2 grade. PA 11/4HNTs nanocomposite has the highest tensile strength, flexural strength compared to other PA 11/HNTs nanocomposites. PA 11/4HNTs nanocomposite can be suggested as an optimum formulation with balanced mechanical properties in terms of toughness

Carbonized rice husk and cocopeat as alternative media bed for aquaponic system

The study evaluates the suitability of carbonized rice husk and cocopeat substrates as alternative media bed in aquaponics unit for cultivation of red Nile tilapia and Gynura procumbens. Area occupied by the aquaponics unit is about 4.5 m2 and it was operated under equatorial climate conditions. Various substrates namely lightweight expanded clay aggregate (LECA), cocopeat, carbonized rice husk and a mixture of cocopeat-rice husk at ratio 1:1 were prepared using polybags for growing of the longevity spinach. The resultant effects from fish cultivation and plants growth on the water qualities and nitrification efficiency of the aquaponics unit were reported. The aquaponics unit were operated for twelve weeks and the values of pH, temperature, and dissolved oxygen level were measured to be within the range of 6.4-6.9, 27.7-29oC, and 5.5-7 mg·L-1, respectively. Survival rate for fish was 98% with specific growth rate (SGR) and food conversion ratio (FCR) of 6.9% per day and 1.13, respectively. Nutrient deficiency was not evident and plants showed healthy growth with harvest yield ranging between 3.6 and 3.9 kg·m-2. Results attained signified the suitability of utilizing carbonized rice husk and cocopeat as alternatives media bed compared to commercial media bed such as LECA

Mechanical properties of magnesium hydroxide/halloysite nanotubes reinforced polyamide 11 nanocomposites

In this study, polyamide 11 (PA 11) and halloysite nanotubes (HNTs) with varying magnesium hydroxide (MH) contents were prepared using a twin-screw extruder and injection moulding process. The mechanical properties of nanocomposites were investigated. The nanocomposites are made up of 100 phr of PA11 and 4 phr of HNTs, with three different MH loadings of 10, 20 and 30 phr. Tensile and flexural strength showed slightly increase while Young’s and flexural modulus continuously increased with addition of MH. Meanwhile, the impact strength and elongation at break decreases

Color detection using non-target reflectivity plastic optical fiber displacement sensor

A simple plastic optical fiber displacement sensor has been demonstrated as a non-contact color detection device. The sensitivity of the sensor is 0.0228, 0.1718, 0.1122, 0.106, and 0.1267 mW/mm for black, blue, green, red, and white, respectively. The experimental results prove that as the color changes from dark to bright, the peak output power increases proportionally. The proposed sensor is highly stable and persistent, with additional advantages of practicality of design, high efficiency, comprehensive depth of field, and low cost of production, which could be beneficial for applications in the sensing field

Mechanical Properties of High Impact Polystyrene/ Styrene-Butadiene-Styrene Blends

Blends of High Impact Polystyrene (HIPS) with Styrene-Butadiene-Styrene (SBS) have two important applications include restoring the impact resistance, which is lost when flame-retardants are mixed into HIPS, and upgrading HIPS to a super high impact product. The purpose of this research is to study the effect of SBS (TR2000) composition on the mechanical properties of HIPS/SBS blends. The measurement of mechanical properties of HIPS/SBS blends has been made at various compositions. Using a single screw extruder, blends of HIPS/SBS with SBS compositions ranging from 0-12 phr were prepared and the specimens for mechanical evaluations were injection-molded. The mechanical test such as tensile test, flexural test, and impact test were carried out. Incorporation of rubbers in the blends increases Izod impact strength. On the other hand, tensile strength and flexural modulus were decrease with increasing the composition of SBS

Chemical resistance evaluation of polystyrene / polypropylene blends : effect of blend compositions and SEBS comtent

The present study investigates the effect of styrene-b-(ethylene-co-butylenes)- b-styrene (SEBS) and blend ratio on the chemical resistance of PS/PP blends. Using a Brabender PL2000 twin-screw extruder, blends of PS rich PS/PP (composition ranging of 90–60 wt % PS) containing different amount of SEBS were prepared and injection moulded to be evaluated for chemical resistance. The results showed that the chemical resistance of PS to acetone and tetrahydrofuran (THF) increased with increasing PP content. The chemical resistance of PS/PP blends increased with increasing SEBS content at relatively lower PP content but decreased with increasing SEBS content at higher PP content. Dynamic mechanical analysis showed that 60/40/25 PS/PP/ SEBS blends had better miscibility than 60/40/5 PS/PP/SEBS blends. However better miscibility did not result in enhanced chemical resistance since SEBS itself was effected by the chemical