Search

The controlled grafting of polymers from small- and macro-molecular substrates is an essential process for many advanced polymer applications. This usually requires the pre-functionalization of substrates with an appropriate functional group, such as a RAFT agent or ATRP initiator, which requires additional synthetic steps. In this paper, we describe the direct grafting of RAFT polymers from carboxylate containing substrates via photochemical radical decarboxylation. This method utilizes the innate functional groups present in the substrates, and achieves efficient polymer initiation in a single step with excellent control of molecular weight and dispersity.

Cobalt-mediated radical polymerizations (CMRPs) have been initiated by the radical decarboxylation of tetrachlorophthalimide activated esters. This allows for the controlled radical polymerization of activated monomers across a broad temperature range with a single cobalt species, with the incorporation of polymer end groups derived from simple carboxylic acid derivatives and termination with an organozinc reagent. This method has been applied to the synthesis of a polymer/graphene conjugate and a water-soluble protein/polymer conjugate, demonstrating the first examples of CMRP in graphene and protein conjugation.

Indonesia is one of the largest spice-producing regions such as the Java Cardamom (Amomum compactum). The cardamom can be converted into derivative products in the form of cardamom essential oil. In this work, we attempted to extract the essential oil from the cardamom by comparing two methods of extraction which are the steam distillation and the simple distillation. The optimization factors considered on the extraction yield were solvent (ethyl acetate and n-hexane) and extraction time (3-6 h). The extraction yield obtained by both methods in ethyl acetate solvents was almost equal to that obtained in n-hexane. Also, the result obtained revealed that the extraction yield increased with time. The optimum essential oil yield was obtained by the simple distillation method in 6 hours duration time using n-hexane solvent giving the yield of 6.3 %. Gas Chromatography-Mass Spectrometry (GC-MS) was used to identify the chemical composition of the extracted oil. The results showed that the chemical composition of the essential oils is different in each extraction time. The main compounds in all oil samples were eucalyptol and camphene among four other constituents. The concentration of eucalyptol reached an optimum (90.89 - 93.74 %) at 4 – 5 h of distillation times, while the concentration of camphene reached an optimum (52.98 %) at 6 h. The purity of the essential oil was confirmed by Fourier Transform Infra-Red (FTIR). Moreover, this research will help to utilize the cardamom due to its main compounds that act as herbal medicine.

As a tropical country which has abundant of spices, Indonesia is challenged to increase the economic values of spices commodity in raw material form (wet or dry). One way to raise the economic values of these commodities is by modifying into its derivatives. Clove is one of spices commodity which can be processed furthermore into an essential oil. By transforming clove from raw material to essential oil, the economic value increases from 2 to 20 times per kilogram. In this present research, the extraction time of clove oil using steam hydro distillation is reported. The distillation procedure was conducted in various times, that was in 3, 4, 5, and 6 hours. Furthermore, the clove oil sample that obtained from optimum extraction time was characterized using FTIR and GCMS. Then the result was compared to the commercial clove oil (100 % of purity). In support of sustainability process, then the clove buds waste from steam distillation were challenging to be one of eco-friendly packaging candidates. Two compositions of waste and additional material have been investigated in this study. It found that the best composition was composed of clove buds waste powder: recycled paper (7:3). During the casting process, some additives material was added such as tapioca (20%) and chitosan (1 %) in acid solution in order to improve its mechanical properties. Furthermore, thermal degradability of the eco-friendly packaging was studied. It was started to degrade at 286.58oC. According to this research, the cloves buds’ cardboard was quite potential to be developed as commercial eco-friendly packaging.

A family of thermoresponsive poly(

Cobalt-mediated radical polymerisations (CMRPs) have been initiated by the radical decarboxylation of tetrachlorophthalimide activated esters. This allows for the controlled radical polymerisation of both activated and less activated monomers across a broad temperature range with a single cobalt species, with incorporation of polymer endgroups derived from simple carboxylic acids derivatives and termination with an organozinc reagent. This method has been applied to the synthesis of a water-soluble protein/polymer conjugate, demonstrating the first example of CMRP in protein conjugation.

Pada penelitian ini, kami mempelajari colorimetric assay yang melibatkan 4-(2-pyridilazo)-resorcinol (PAR) untuk analisis kuantitatif jumlah gadolinium bebas dan yang terikat dengan ligan dalam sistem. Penelitian ini adalah studi awal untuk mengamati pola kompleksasi antara Gd 3+ dan molekul target yang dilakukan dalam 100 mM bufer MES pH 5.5. Konstanta pengikatan (Log K) dari kompleks Gd 3+ -PAR (1-1) pada pH 5.5 adalah 4.41 ± 0.09 M -1 . Karena metode ini hanya menggunakan UV-Vis Spektroskopi, disimpulkan bahwa colorimetric assay yang melibatkan PAR adalah metode yang cepat dan murah untuk menganalisis aktivitas pengikatan antara Gd 3+ dan ligan target. Katakunci: Gadolinium, colorimetric assay , agen pengkontras MRI. In this research, we study a colorimetric assay employing 4-(2- pyridylazo )- resorcinol (PAR) for quantifying the chelated and free gadolinium in the system. This is a preliminary study in order to observe the complexation behavior between Gd 3+ and targeted molecules. This was carried out in 100 mM MES buffer at pH 5.5. The binding constant (Log K) of the Gd 3+ -PAR (1:1) complex at pH 5.5 is 4.41 ± 0.09 M -1 . Since this method only uses UV-Vis spectrometry, it is concluded that colorimetric assay employing PAR is a fast and inexpensive method in order to analyze the binding activity between Gd 3+ and targeted ligands. Keywords : Gadolinium, colorimetric assay, MRI contrast agent.