scholarly journals Natural rubber latex as a resist medium for batik production

2019 ◽  
Vol 37 (2) ◽  
pp. 126-141
Author(s):  
A. E. Asmah ◽  
V. Okpattah ◽  
E. Koomson

To reduce the dependency of the exportable Paraffin wax, as a major resist component in batik making, the study examined the possibility of using the locally available natural rubber latex extracted from the natural rubber tree as a resist medium for batik production. A series of experiments were conducted using the rubber latex on mercerized cotton as a resist via stamping, tjanting and screen printing techniques. The experimental and descriptive methods under the qualitative research approach were the main instrument deployed. It was realized based on the various experiments conducted, that the natural rubber latex coagulates when expose to air, making its application difficult to adhere well on the fabric. To resolve this, a concentrated ammonia solution and poly vinyl acetate were added to the freshly tapped natural rubber latex to prevent coagulation, prolong its liquid state and improve its viscosity to make it applicable onto the cotton fabric. Though the unpleasant smell remains after de-latex, the project proved successful after a series of washing to reduce the smell of the turpentine. Further research is suggested to examine how the smell of the turpentine can be reduced to avoid eroding the brightness of the dyed fabric, especially when dyed with lighter colours such as orange and yellow.Keywords: Natural rubber latex; ammonia solution; poly vinyl acetate; mercerized cotton; batik

2013 ◽  
Vol 747 ◽  
pp. 103-106 ◽  
Author(s):  
Prapaporn Boonme ◽  
Hasleena Boontawee ◽  
Wirach Taweepreda ◽  
Wiwat Pichayakorn

The mucous liquid of Hevea brasiliensis or Para rubber tree, called natural rubber latex (NRL), composes of cis-1,4-polyisoprene which can form a patch under suitable formulation. In this study, blank and 5% lidocaine-loaded NRL patches were formulated and then characterized for physicochemical properties as well as evaluated in vitro drug release and stability. The patches were observed for their appearances. Surface morphology of the patches was investigated using a SEM. XRD was employed to study the crystallinity of the drug, the patch, and the drug-loaded patch. The extractions of lidocaine-loaded patches were analyzed for drug contents by HPLC. In vitro drug release study was performed using modified Franz diffusion cells. The patches at initial preparation and after kept at 4, 25, and 45 °C for 3 months were investigated for the stability determination. The results suggested that NRL could be used as a main component in pharmaceutical transdermal patches with acceptable physicochemical properties. Lidocaine-loaded NRL patches provided desirable drug release but high storage temperatures could age the patches resulting in darken color and lower release amount.


2017 ◽  
Vol 866 ◽  
pp. 195-198
Author(s):  
Rakchanok Promudom ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong

The physical and mechanical properties of Portland cement (PC) - natural rubber latex (NRL) - fly ash (FA) composites have been investigated. The latex per cement ratios that use in this experiment are 0, 5, 7.5 and 10% by weight of cement. Portland cement (PC) was partially replaced with fly ash 0-40% by weight of binder. Water to cement ratio were used in range of 0.305-0.385 (by weight not include water in latex). Nonionic surfactant was added in cement before mixed with natural rubber latex. In addition, to provide latex from natural rubber latex, the ammonia solution is added into natural rubber. The specimens were packing into an iron mold which sample size of 4x4x16 cm3. Moreover, the PC-NRL-FA composites were cured in water for 7 and 28 days at room temperature before measurement. Then, mechanical properties (flexural strength) and microstructure were studied.


BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 3168-3181 ◽  
Author(s):  
José Antonio Fiorote ◽  
Alair Pereira Freire ◽  
Dasciana de Sousa Rodrigues ◽  
Maria Alice Martins ◽  
Larissa Andreani ◽  
...  

Rubber tree and oil palm are industrial crops cultivated in the same climate and environment. These plants are used to prepare nanocomposites of natural rubber and cellulose from empty fruit bunches, an abundant residue in the palm oil industry. For this study, the cellulose particles were extracted from the bunches and subjected to enzymatic hydrolysis or microfibrillation to produce nanostructured particles. The nanoparticles were blended with natural rubber latex in an aqueous medium, and the mixture was dried. The properties of the nanocomposites were compared to those of pure natural rubber and unprocessed cellulose composites. The mechanical properties of the natural rubber can be modified by the cellulose content and morphology. As a consequence, it is possible to modulate the material properties by changing only the filler morphology. The use of microfibrillated cellulose had stronger reinforcement effects. The thermal properties of natural rubber were not affected by the addition of cellulose.


2012 ◽  
Vol 2 (2) ◽  
pp. 58-64 ◽  
Author(s):  
Hien Nhu Nguyen ◽  
Thao Thanh Luong

Rubber tree is one of the main plants which play an important role in the economy of Southeastern region, Vietnam. Approximately 90% of Vietnamese natural rubber latex is exported as raw products. The preliminary process of natural rubber latex discharges a large amount of wastewater to the environment. In Vietnam, there are many available technologies set up and operated for treatment wastewater of rubber latex processing. However, the effluent quality is still poor and the concentration of pollutants is higher than the required national technical regulation on the effluent of the natural rubber processing industry (QCVN 01:2008/BTNMT). Thus, this paper summarizes various technologies and methods currently applied for the treatment of latex processing wastewater in Vietnam. Additionally, the new effective methods being researched and applied in Thailand and Malaysia are also mentioned (countries with the highest production of natural rubber in the world). This paper also provides a screening of treatment technologies for reducing environmental pollution and contributing to high-quality effluent for meeting the required standard. Cao su là một trong những cây trồng chính và đóng vai trò quan trọng trong nền kinh tế của miền Đông Nam Bộ, Việt Nam. Sản phẩm từ cây cao su thiên nhiên tại Việt Nam chủ yếu là xuất khẩu (khoảng 90%), tuy nhiên chỉ mới là dạng cao su thiên nhiên sơ chế. Quá trình sơ chế mủ cao su thiên nhiên thải bỏ một lượng lớn nước thải vào môi trường. Ở Việt Nam, hiện tại có rất nhiều công nghệ xử lý nước thải sơ chế mủ cao su đã được thiết lập và vận hành. Tuy nhiên, nồng độ ô nhiễm trong nước thải sau quá trình xử lý còn cao so với tiêu chuẩn yêu cầu (QCVN 01:2008/BTNMT). Vì vậy, bài báo này tóm tắt những công nghệ và phương pháp khác nhau được sử dụng để xử lý nước thải sơ chế mủ cao su tại Việt Nam gần đây. Thêm vào đó, những phương pháp mới và hiệu quả đang được nghiên cứu và áp dụng tại Malaysia và Thái Lan, những quốc gia có sản lượng sản xuất mủ cao su cao nhất trên thế giới cũng được giới thiệu. Bài báo này cũng cung cấp sự đa dạng của những phương pháp xử lý nhằm giảm thiểu ô nhiễm môi trường và góp phần đảm bảo chất lượng nước đầu ra đạt tiêu chuẩn cho phép.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Isabela de Castro Sant’Anna ◽  
Ligia Regina Lima Gouvêa ◽  
Maria Alice Martins ◽  
Erivaldo José Scaloppi Junior ◽  
Rogério Soares de Freitas ◽  
...  

AbstractThe objective of this study was to evaluate the genetic variability of natural rubber latex traits among 44 elite genotypes of the rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Müell. Arg.]. Multivariate analysis and machine learning techniques were used, targeting the selection of parents that demonstrate superior characters. We analyzed traits related to technological or physicochemical properties of natural rubber latex, such as Wallace plasticity (P0), the plasticity retention index [PRI (%)], Mooney viscosity (VR), ash percentage (Ash), acetone extract percentage (AE), and nitrogen percentage (N), to study genetic diversity. Multivariate [unweighted pair group method with arithmetic means (UPGMA) and Tocher)] and machine learning techniques [K-means and Kohonen’s self-organizing maps (SOMs)] were employed. The genotypes showed high genetic variability for some of the evaluated traits. The traits PRI, Ash, and PO contributed the most to genetic diversity. The genotypes were classified into six clusters by the UPGMA method, and the results were consistent with the Tocher, K-means and SOM results. PRI can be used to improve the industrial potential of clones. The clones IAC 418 and PB 326 were the most divergent, followed by IAC 404 and IAC 56. These genotypes and others from the IAC 500 and 400 series could be used to start a breeding program. These combinations offer greater heterotic potential than the others, which can be used to improve components of rubber latex quality. Thus, it is important to consider the quality of rubber latex in the early stage of breeding programs.


Author(s):  
Nayrim Brizuela Guerra ◽  
Giovana Sant'Ana Pegorin ◽  
Miguel Henrique Boratto ◽  
Natan Roberto de Barros ◽  
Carlos Frederico de Oliveira Graeff ◽  
...  

2015 ◽  
Vol 659 ◽  
pp. 458-462 ◽  
Author(s):  
Teerawan Wannuch ◽  
Adun Nimpaiboon ◽  
Jitladda Sakdapipanich

Natural rubber (NR) latex collected from Hevea brasiliensis rubber tree exists as a colloidal suspension with 30% dry rubber content (DRC). For convenient use and transportation, the latex is concentrated by centrifugation process. Through this process, the 60% DRC concentrated NR latex and 5% DRC skim latex as a by-product were produced. After using acid coagulation of skim latex, the skim rubber is obtained to use as a low-grade application due to high amount of non-rubber components as impurities. The water portion remaining after the coagulation of skim rubber consists of various water-soluble materials such as sugars, lipids, proteins and minerals, which can cause the water pollution if serum is directly discharged into the environment without proper treatment. However, 1.5% of L-quebrachitol was found in skim latex. It can be used in many applications such as a starting material for the synthesis of bioactive materials and inositol pharmacy. Thus, this work is an attempt to investigate the most effective extraction method of L-quebrachitol from skim latex. It was found that the appropriate solvent for extraction L-quebrachitol at high temperature and for recrystallization at low temperature is ethanol. The yield of L-quebrachitol about 2-3% by weight of solid serum was obtained. Moreover, a sweetness and antibacterial activity were also studied for its further applications. It was found that the sweetness of L-quebrachitol was twice than that of sucrose. No antibacterial activity of L-quebrachitol against Staphylococcus aureus and Streptococcus mutans was found.


2015 ◽  
Vol 804 ◽  
pp. 124-128
Author(s):  
Nittaya Jaitanong ◽  
Tanapong Chaipunti

The microstructure and mechanical properties of Portland cement (PC)- natural rubber latex (NRL)- rice husk ash (RHA) composites have been investigated. The proportions of PC-NRL-RHA composites with NRL to cement ratio (NRL/C) that use in this experiment were 0, 0.10, 0.15 and 0.20 respectively. Portland cement (PC) was partially replaced with rice husk ash at 20% by weight of binder. The rice husk ash (RHA) was ground for 180 minutes before using. Water to cement ratio (W/C) equal of 0.5 by weight not include water in NRL. Nonionic surfactant was added in cement before mixed with NRL. In addition, to provide latex from natural rubber, the ammonia solution is added into natural rubber. The specimens were casting in standard mold which samples size of 50x50x50 and 40x40x160 mm3 respectively. Moreover, the PC-NRL-RHA composites were cured in water for 3, 7 and 28 days at room temperature before measurement. Then, mechanical properties (compressive strength and flexural strength) and microstructure were studied.


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