Judul: Kajian Pemanfaatan Getah Pinus (Pinus merkusii) Sebagai Bahan Baku Perekat
Abstrak: Pine merkusii included to multipurpose tree species that developed and expanded continually to produce timber, gums, and as conservation land. Almost all parts of the tree can be utilized. Part of the tree that has high values is the pine gum. Processing of pine resin is widely used in printing ink industry, coating industry, and adhesive industry. Adhesive substance is a material that can be joined with the same or different type of object through bonding process or surface contact, so the body of joint object is resist to separation effort. In the production of pine gum adhesive substance, esterification process carried out to improve the adhesive power. This research aims to study the process of making adhesive substance from pine gum esters, and also to determine the effect of acid number, ester number, glycerol number and catalyst concentration on adhesive strength of the adhesive products. Stages of this research is the characterization of pine gum raw materials; esterification using KOH catalyst with concentration 1.5 and 10% by weight of pine gum, and moles of glycerol 1.1, 1.5, and 2 mol; making of the adhesive substance and determination of the best adhesive substance based on its best adhesive strength. Conducted preliminary research is the characterization of raw materials of pine gum, and then continued with the main research that is esterification of pine gum using alkaline catalyst (KOH), and making of the adhesive substance of the pine gum esterification. The treatment that used is the concentration of KOH catalyst (1%, 5%, and 10%) and the mole of glycerol (1.1 mol, 1.5 mol, and 2 mol). The esterification results of the pine gum tested through acids numbers, esters numbers, and free glycerol levels by comparing between the unwashed pine gum esters and the washed. The esterification results are made into adhesive substance. Then the surface area of adhesive strength and the adhesive strength of adhesive substance tested with shear stress (shear strength) of the adhesive strength and test. Based on preliminary research results, the characteristics of pine gum that was obtained is a liquid, slightly yellow color, soluble in ethanol solvent ratio of 90 percent with 1 ml of pine resin:1 ml of ethanol, acid number 125.66, and viscosity Cp 8693.14. The results of measurements showed that the adhesive substance with the code C22 (with KOH catalyst 5%, 1.5 mol glycerol, washed) gives a better adhesive strength. The characteristics of adhesive substance with the code C22 are: acids numbers 109.21 and esters numbers 21:18. Based on the observations, it can be concluded that the adhesive substance that was processed with 5% catalyst and 1.5 mole of glycerol with the code C22 is the best adhesive substance compared with others based on its adhesive strength.
Keyword: 

Judul: Characteristic Areca Particleboard’s Adhesive Based on Tannin-Glyoxal of Mangium Bark
Abstrak: Papan partikel merupakan salah satu produk komposit yang terbuat dari campuran partikel dan perekat kemudian dikempa panas. Perekat yang banyak digunakan untuk pembuatan produk panel kayu masih berbasis perekat formaldehida, seperti Urea Formaldehida (UF) dan Fenol Formaldehida (PF) yang memberi pengaruh buruk bagi kesehatan manusia. Salah satu senyawa yang dapat digunakan sebagai substitusi formaldehida pada perekat adalah glioksal. Sebagai perekat, glioksal dapat direaksikan dengan senyawa ramah lingkungan berbasis bahan alam seperti tanin. Salah satu sumber tanin yang melimpah adalah kulit kayu mangium (Acacia mangium Willd.). Hardener ditambahkan dalam proses pembuatan papan partikel pelepah pinang untuk mempercepat reaksi pengerasan perekat dan papan partikel. Namun, rasio formula perekat tanin-glioksal dan penggunaan jenis hardener pada proses pembuatan papan partikel belum diketahui. Oleh karena itu, penelitian ini bertujuan untuk mengidentifikasi karakteristik perekat ramah lingkungan dan bebas formaldehida berbasis tanin-glioksal pada rasio berbeda dan mengevaluasi karakteristik papan partikel pelepah pinang yang dihasilkan pada penggunaan hardener yang berbeda. Proses pembuatan perekat tanin-glioksal dilakukan menggunakan ekstrak kental dari tanin kulit kayu mangium dengan tiga formula yang terdiri dari rasio Tanin : Glioksal (T:G) berbeda, yaitu F1 (T:G = 1:2), F2 (T:G = 1:1) dan F3 (T:G = 2:1). Ekstrak tanin diperoleh dari ekstraksi kulit kayu mangium menggunakan metode maserasi air panas. Perekat dibuat dengan cara mereaksikan tanin dengan NaOH 20% pada suhu 80 °C kemudian ditambahkan glioksal 40% dan tetap dipanaskan selama 1 jam. Karakterisasi perekat dilakukan berdasarkan hasil analisis menggunakan FTIR, Py-GCMS, XRD, gel time meter, rheometer, dan DMA. Papan partikel pelepah pinang dibuat menggunakan kadar perekat TG 10% lalu dikempa pada suhu 150 °C selama 15 menit. Papan dikondisikan selama 14 hari untuk selanjutnya dilakukan pengujian sifat fisis dan mekanis. Hasil analisis FTIR terhadap perekat cair dan padat menunjukkan gugus fungsi pada puncak serapan yang sama namun teridentifikasi adanya gugus C=O pada perekat padat yang berasal dari senyawa glioksal. Senyawa butanadion terbentuk dari reaksi tanin dan glioksal yang dapat dilihat berdasarkan data hasil pirolisis perekat tanin-glioksal. Persentase glioksal yang tinggi akan meningkatkan persentase kristalinitas pada perekat. Hal ini menandakan glioksal mampu membentuk ikatan polimer menjadi lebih baik. Peningkatan ikatan polimer ini juga sesuai dengan peningkatan kekuatan kohesi berdasarkan pengujian reologi. Beberapa sifat fisis dan mekanis papan partikel pelepah pinang yang dihasilkan masih belum memenuhi SNI 03-2105-2006. Namun, penggunaan hardener NH4Cl menghasilkan sifat yang lebih baik dibandingkan papan partikel dengan hardener NaOH. Hasil penelitian menunjukkan bahwa perekat tanin-glioksal dapat digunakan sebagai perekat pada papan partikel pelepah pinang ramah lingkungan., Particle board is a composite product made from a mixture of particles and adhesive, then hot pressed. The adhesives widely used to manufacture wood panel products are still based on formaldehyde adhesives, such as Urea Formaldehyde (UF) and Phenol-Formaldehyde (PF), which harm human health. One of the compounds that can be used as a substitute for formaldehyde in adhesives is glyoxal. As an adhesive, glyoxal can be reacted with environmentally friendly compounds based on natural ingredients such as tannins. One of the abundant sources of tannins is the bark of mangium (Acacia mangium Willd.). Hardener is added in the process of making an areca nut particle board to accelerate
Keyword: ekstraksi tanin, glioksal, NaOH, NH4Cl, perekat tanin-glioksal

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
Keyword: