Hydroxyl-Terminated Saponified Natural Rubber Based on the H2O2/P25-TiO2 Powder/UVC-Irradiation System

Natural rubber (NR), a long-chain hydrocarbon polymer mostly consisting of cis-1,4-polyisoprene units, has a high molecular weight (MW) and viscosity, enabling it to show excellent physical properties. However, NR has no reactive functional group, making it difficult to react with other molecules, especially in manufacturing processes. The functionalized low-molecular-weight NR (FLNR) is a requirement to disperse ingredients into the rubber adequately. Here, the FLNR was prepared by a photochemical degradation process under UVC-irradiation in the presence of H2O2 using P25-titanium oxide (TiO2) powder as a photocatalyst. The optimum condition for the preparation of FLNR was the use of 2.0 g of TiO2 powder per 100 g of rubber and H2O2 at 20% w/w under UVC-irradiation for 5 h. The hydroxyl groups were found on the NR chains due to the chain-scission of polyisoprene chains and hydroxyl radicals in the system. The weight average MW of NR decreased from 12.6 × 105 to 0.6 × 105 gmol−1, while the number average MW decreased from 3.3 × 105 to 0.1 × 105 gmol−1.

The use of Polystyrene from Ballpen Barrels and Wood Ash as Additives in Making Lightweight Bricks.

This study aimed to determine the ability of polystyrene in ballpen barrels of making a brick to be more compacted than the ordinary clay bricks. Polystyrene is a synthetic aromatic hydrocarbon polymer made from the monomer styrene that also makes a brick denser. The Wood ash from burned wood are usually used by the gardeners as a good source of potash. Wood ash has an ability of making the bricks lighter than the usual clay bricks. Additional wood ash is better than coal ash, because coal ash has a dangerous chemicals that may harm human. The goal of this study is to lessen the ballpen barrels and wood ash that are not disposed properly and make this in a creative way. Five test was conducted to determine the potential of polystyrene and wood ash namely water absorption test, drop test, efflorescence test, compressive test and heat resistance test. Based from the data gathered, it concluded that polystyrene from ballpen barrel and wood ash with the ratio of 50% Cement, 25% Wood Ash, 25% Ballpen Barrels is effective additives in production of lightweight

Poly(meta/para-Terphenylene-Methyl Piperidinium)-Based Anion Exchange Membranes: The Effect of Backbone Structure in AEMFC Application

A series of poly(meta/para-terphenylene-methyl piperidinium)-based anion exchange membranes devoid of benzylic sites or aryl ether bonds, that are vulnerable to degradation by hydroxide ions, are synthesized and investigated for their application as novel anion exchange membranes. The copolymers are composed of both linear para-terphenyl units and kink-structured meta-terphenyl units. The meta-connectivity in terphenyl units permits the polymer backbones to fold back, maximizing the interactions among the hydrocarbon polymer chains and enhancing the peripheral formation of ion aggregates, due to the free volume generated by the kink structure. The effects of the copolymer composition between para-terphenyl and meta-terphenyl on the morphology and the electrochemical and physicochemical properties of the corresponding polymer membranes are investigated.

INVESTIGATION IN THE USE OF COWPEA CHAFF AS AN ADDITIVE FOR NATURAL RUBBER.

Natural rubber is a gummy liquid obtained from the sap fluid of the tree Hevea brasilensis. It is a natural hydrocarbon polymer of 2-methyl-1-3-butadiene (isoprene), which contains one double bond per repeating unit, whose structural arrangement typifies that of a cis-isomer (cis-polyisoprene). Natural rubber in its raw gum state is tacky, fairly elastic but suffers some limitations such as poor resistance to weathering condition, low tensile strength and hence additives are always added to improve on the limitations of the natural Rubber. Most additives are imported hence constituting additional cost. Cowpea chaff was used in this study as one of the additives. The cowpea chaff was chosen for this research due to its availability and cost since it is a waste material and expected to reduce cost of production. The cowpea chaff was grinded and sieved to fine particles (powder) using 100µm. The cowpea chaff powder was divided into portions and part were modified via nitration. The modified and unmodified cowpea chaff powder were characterized to determine the Ash content, Moisture content, Volatile content, pH, Loss on ignition, X-ray florescence (XRF) analysis was carried out to ascertain the elemental composition and Infra-red spectroscopy (FT-IR) to determine the functional groups and extent of the reaction of the samples. Each of the portions were compounded with Natural Rubber (NR) using calcium carbonate as control. The physico-mechanical properties of the vulcanizates obtained were determined. The study showed that chemically modified and unmodified cowpea chaff powders were good additives (softeners). Based on the parameters tested, it can be concluded that cowpea chaff can be substituted with CaCO3 filler in NR vulcanizates.

Multi-phenyl structured aromatic hydrocarbon polymer

Multi-phenyl structured random polymer was synthesized via condensation polymerization reaction by applying different monomer ratios and characterized by various spectroscopic methods (FT-IR, 1H NMR). The prepared polymers showed good thermooxidative stability up to 400 ºC. The surface morphology was studied by FESEM that showed the good linkage among the polymer chains. The EDS data of poly(fluorenylene ether ketone), PFEK; demonstrated that all the monomers participated in the copolymerization reaction. Inherent viscosity values of the polymers were obtained in the range of 0.76∼1.12 dL g-1. The polymers’ yield was within 85~90%. The obtained results indicate that the multi-phenyl structured polymer will be the good candidates to prepare the effective aromatic hydrocarbon polymer electrolyte membrane. Bangladesh J. Sci. Ind. Res.55(2), 139-146, 2020