Polypropylene utilization has been rapidly growing since its discovery in 1954 due to its unique combination of mechanical and chemical properties. Most polypropylene manufacturer use MgCl2‐supported Ziegler–Natta catalyst comprises of MgCl2 support, internal donor, and active site of TiCl4. Addition of cocatalyst and external donor are also necessary in polymerization process. External donor, also known as selectivity control agent is often used in polypropylene production for stereo‐selectivity control as well as for product properties adjustment. The effect of two different silane‐based donor cyclohexylmethyldimethoxysilane (C‐Donor) and dicyclopentyldimethoxysilane (D‐Donor) on the product properties are studied. The impact is observed in homopolypropylene with similar melt flow rate synthesized with Ziegler–Natta catalyst. Product properties such as resin fundamental properties (xylene soluble, color), film physical properties (tensile strength, elongation), and film optical properties (clarity, haze, gloss) are observed and evaluated. From the series of testing, both C‐donor and D‐donor products perform comparable fundamental, physical, and optical properties. This study shows that the type of silane‐based external donor gives only slight effect to homopolypropylene product properties.
Asthma was a chronic imflammatory disorder that causes bronchospasm and bronchoconstriction which can cause respiratory muscles to experience weakness, resulting in the decreased of respiratory ability. Asthma exercise improves respiratory ability in asthma disorders. This study aims to identify the effect of asthma exercise on the respiratory ability of asthma patients at Asthma Poly Bangil Regional General Hospital. This type of research is pre experiment with pre test-post test design. The sampling technique uses total sampling so that the number of samples were 31 people. Data analysis using statistical test t test bound with a significant level of α : 0.05. The results showed the average respiratory ability (APE) before asthma exercise were 208 lt / min gymnastics and after asthma exercise increased to 304 lt / min, a statistical test obtained p value: 0,000 (<α: 0,05) there was an asthma exercise effect on the respiratory ability in asthma patients at Asthma Poly Bangil Regional General Hospital. It is recommended for asthmatics to carry out asthma exercises regularly in order to improve their breathing ability and improve the quality of life.Keywords: Asthma Exercise, Respiratory Ability
The use of plastics, especially High-Density Polyethylene (HDPE) film has increased rapidly in recent years due to its low cost, lightweight and excellent mechanical properties which is depended on the extrusion condition in the owner’s film fabrication machine. The blown film process is the common process used to make a thermoplastic film in large volumes. However, many research performed long ago in the mechanical properties of polyethylene only concerned on the effect of conventional processing parameters such as temperature and pressure in blown film machines and neglected the significant effect of critical extrusion conditions. We did the study to know the effect of critical extrusion conditions such as output rate, blow-up ratio (BUR) and neck-point height (NPH) which was intended to get the optimum film fabrication conditions in a blown film extrusion machine. Each parameter was performed in five different conditions by increasing one parameter and controlling the other. The resin first melted, conveyed, and delivered before finally blown to form the film. The mechanical properties observed were impact resistance, tensile strength, elongation, tear strength, and young modulus. The result indicates that increasing the output rate, BUR and NPH imparted in the film’s orientation balance, bubble shape, relaxation, and crystallization effects will lead to the increase of impact resistance, decrease of tear strength, and balance of film direction properties. The excessive and low amount of output rate, BUR and NPH are not desirable as it decreases the mechanical properties from HDPE film whether in mechanical direction or transverse direction. Hence, the optimum operating condition depends on which mechanical properties that needed to be achieved by film fabricators.
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