ABSTRAKPanel kayu merupakan produk yang terbuat dari bahan kayu yang direkatkan dengan menggunakan resin, bahan perekat yang digunakan dalam produksi kayu lapis merupakan resin urea-formaldehid (UF). ...Resin UF adalah resin thermosetting yang terbuat dari urea dan formaldehid yang akan mengeras jika dipanaskan dan dapat dicetak ulang. Pada penelitian ini, pembuatan resin UF menggunakan bahan baku dari Urea Formaldehyde Concentrate (UFC). Tujuan dari penelitian ini mempelajari pengaruh perubahan sifat dan kinerja resin UF dari UFC, pengaruh rasio molar pada tahap metilolasi dan kondensasi, dan menguji efektivitas resin UF melalui aplikasi pembuatan panel kayu dengan cara menguji Internal Bonding (IB) Strength dan emisi formaldehid. Berdasarkan penelitian yang telah dilakukan maka didapatkan bahwa pembuatan resin UF dengan bahan baku UFC memiliki gel time yang lebih panjang sehingga menurunkan IB Strength, dan free formaldehyde yang rendah sehingga emisi formaldehid akan menurun dibandingkan dengan nilai IB Strength maupun emisi formaldehid dari resin UF dari urea dan formaldehid.ABSTRACTWood panel are a product made of a wood inggriidients glued together by using resin. The main adhesive used in plywood production is urea-formaldehyde resin (UF). UF resin is a thermosetting resin made from urea and formaldehyde, where this resin to be hardened if heated and reprinted. The purpose of this research is affects changes in properties and performance from UF resin made from UFC, effects of molar ratio at the metylolation and condentation stage, and tests the effectiveness of UF resin with a wooden paneling application by testing Internal Bonding (IB) Strength, and formaldehyde emission. According to this research it has been obtained that UF resin with UFC material has a lengthly gel time therefor lower IB Strength value, and low free formaldehyde so that formaldehyde emission will decreased when compared with IB Strength value as well as formaldehyde emissions from UF resin with urea and formaldehyde materials.
The objective of the study is to know the content of formaldehid of salted fish which taken from tradisional market in Bangkalan and Sampang. The experiment conducted at the Laboratory of ...Agroindustry Technology, Faculty of Agriculture, Trunojoyo University Madura on June 2010. This research uses reagent chromotophic acid (C10H6Na2O8S2.2H2O). The test is positive indicated by the red through the purple color. The process continued by spectrophotometer. The result of the research shows that all samples from Kamal, Socah, Bangkalan and Sampang markets contain formaldehid i.e: 29,10 mg/kg, 30,65 mg/kg, 49,26
mg/kg, 44,14 mg/kg respectively.
Formaldehyde has applications in many industrial processes, including synthesis of resins and syntans to be used in the retanning process of leather. When resins are employed, they can hydrolyse, ...releasing formaldehyde. Due to the carcinogenicity of formaldehyde, its presence in leather should be avoided or kept below allowable limits.
The aim of this study is to determine the effect of polyphenols contained in vegetable compounds (mimosa, quebracho and tara) in the reduction of the formaldehyde content in leathers treated with resins synthesized with formaldehyde (melamine-formaldehyde and dicyandiamide-formaldehyde). The formaldehyde content in leathers treated only with resin increases with time while the formaldehyde content in leathers treated additionally with vegetable compounds is reduced. The lower the formaldehyde content in the leather, the higher the ability of vegetable compounds to reduce such content. Mimosa shows the strongest ability to reduce the formaldehyde content, and this capacity increases with ageing. The addition of 4% (on shaved wet-blue weight) of mimosa gives rise to an 85% reduction in the formaldehyde content 140 days after leather processing of split hides treated with a formaldehyde resin of low formaldehyde content. However, this reduction is 68% in splits hides treated with a resin of high formaldehyde content. This is of great importance in baby’s leather articles, in which the formaldehyde content is low; therefore, the addition of a small amount (3%) of vegetable compounds (especially mimosa) guarantees that the formaldehyde content is below the allowed limits (16 mg/kg in the most restrictive regulation). Reducing the formaldehyde content using the polyphenols contained in vegetable compounds constitutes a good alternative not only in the leather sector but also in other industrial sectors (wood, textile, etc.) that use formaldehyde resins.
•Plant polyphenols reduce the content of toxic formaldehyde in leather.•Formaldehyde content in leather treated with formaldehyde resins increases with ageing.•Plant polyphenols gradually diminish the formaldehyde content in leather.•Mimosa extract shows the highest sequestering capacity towards formaldehyde.•A greater offer of vegetable compound leads to a higher reduction of formaldehyde content.
Mikroenkapsulasi merupakan salah satu cara untuk mengatur pelepasan bahan aktif dan melindungi bahan aktif yang dapat melarut secara konvensional dengan pelapisan dari bahan semi permeable, tidak ...larut dalam air, atau bahan berpori yang permeable. Dengan mengatur ketebalan dari dinding mikrokapsul, difusi dari senyawa aktif yang dienkapsulasi dapat terkontrol. Penelitian ini terfiri dari 2 tahap, yaitu pembuatan resin melamin urea formaldehid dan pembuatan mikrokapsul. Yang dipelajari dari penelitian ini adalah mendapatkan karakter dari mikrokapsul Melamin Urea Formaldehid (MUF) yang dibuat dengan kondisi proses yang berbeda. Pembuatan mikrokapsul MUF dilakukan dengan metode in-situ polimerisasi pada suhu 50 °C, pH 3, waktu homogenisasi 30 menit, dan waktu mikroenkapsulasi 2 jam dengan bahan yang digunakan terdiri dari larutan resin prepolimer melamin urea formaldehid, diazinon, minyak kelapa sawit, serta surfaktan sodium dodecyl sulfat (SDS) dan polivinil alkohol (PVA). Karakterisasi terhadap produk mikrokapsul yang dihasilkan dilakukan dengan menggunakan mikroskop optik. Hasil penelitian menunjukkan bahwa mikrokapsul MUF memiliki kisaran diameter 50 sampai 160 µm. Tanpa penambahan surfaktan, hasil mikrokapsul memiliki ketebalan 13,8 µm dan dengan penambahan SDS dan PVA tebal mikrokapsul yang dihasilkan sebesar 7,55 µm
Due to its carcinogenic character, the presence of formaldehyde in leather continues to be a subject of great concern. By using formaldehyde scavengers, it is possible to reduce the formaldehyde ...content in leather. In this work, the potential ability of three different compounds (ethylene urea, pyrogallol and gallic acid) to reduce the formaldehyde content in splits leathers treated with formaldehyde resins (melamine-formaldehyde and dicyandiamide-formaldehyde) is assessed. This capacity is compared with that of a fourth scavenger (hydroxylamine sulphate) already used in tanneries. The evolution of the formaldehyde content with time is also considered, as well as the potential coadjuvant effect of other compounds such as mimosa extract and an acid dye (Acid Black 234). Hydroxylamine sulphate initially showed the highest ability to reduce formaldehyde content. However, after a certain time, this ability proved to be inferior to the ability of other compounds due to the reversibility of the reaction between hydroxylamine and formaldehyde. Pyrogallol showed a higher ability than gallic acid when used in the final wash of leather processing. However, the treatment with pyrogallol results in a darkening of the leather; this darkening limits its use. Gallic acid may be a good alternative to formic acid as the final fixing agent in leather processing when the presence of formaldehyde in leathers is suspected. The use of gallic acid in the final wash or as a fixing agent fulfils the formaldehyde content limit (65–75 mg/kg) of the major brands in leather goods in direct contact with the skin. The addition of 2% of gallic acid in the final wash of leather processing resulted in formaldehyde content reductions that varied from 65% to 85%. However, further experiments are required to assess the influence of gallic acid on the fastness properties and the coloration acquired by the treated leathers. The joint effect of gallic acid in the final wash or as a fixing agent and mimosa extract as a retanning agent in formaldehyde content reduction is even enhanced by subsequently using a dye with amino groups in its chemical structure. Reducing the formaldehyde content by using scavengers can contribute to the achievement of a cleaner production in those sectors (leather, textile, wood) that use formaldehyde resins.
•Formaldehyde must be restricted due to its proven impact on humans and eco-systems.•Scavengers reduce at different extent the formaldehyde content in leather.•Hydroxylamine is environmentally toxic and its scavenging ability lowers with time.•Pyrogallol has a high reduction ability but its use results in leather darkening.•Gallic acid may be a good alternative as formaldehyde scavenger.
Penelitian kadar formaldehid alami pada beberapa jenis ikan laut selama penyimpanan dalam es curai telah dilakukan untuk mengetahui intensitas pembentukan formaldehid alami oleh ikan setelah mati. ...Hasil penelitian ini diharapkan dapat menjadi acuan untuk menduga kemungkinan dilakukannya penyalahgunaan formalin pada ikan. Penelitian dilakukan terhadap ikan laut hidup yang terdiri dari 6 jenis ikan yaitu bawal bintang (Trachinotus blochii), kakap putih (Lates calcarifer, bloch.), cobia (Rachycentron canadum), bandeng (Chanos chanos), kerapu cantrang Epinephelus fuscoguttatus-lanceolatus), dan kakap merah/jenaha (Lutjanus johnii). Pengambilan sampel di lapangan dilakukan secara bertahap dan setiap pengambilan terdiri dari dua jenis ikan. Ikan tersebut dibawa ke laboratorium Balai Besar Penelitian dan Pengembangan Pengolahan Produk dan Bioteknologi Kelautan dan Perikanan (BBP4BKP) dalam keadaan hidup, kemudian ikan dimatikan dengan cara hipotermal (dimasukkan dalam air es dengan suhu 0–4oC selama 30 menit). Setelah mati ikan dibagi menjadi 3 kelompok dan disimpan dalam peti insulasi yang berisi es dengan perbandingan ikan : es adalah 1 : 3. Pengamatan dilakukan setiap 3 hari selama 18 hari. Parameter yang diamati adalah kadar formaldehid, trimethil amin (TMA), trimethil amin oksida (TMAO) dan kadar total volatile base (TVB) serta komposisi proksimat pada hari pertama. Hasil penelitian menunjukkan bahwa kandungan formaldehid alami pada hari ke 12 penyimpanan pada bawal bintang, kakap putih, cobia, bandeng, kakap merah, dan kerapu cantrang berturut-turut adalah 0.954; 1.572; 0.964; 0,715; 1.381; dan 1.303 ppm. Pada saat itu kondisi ikan masih segar dengan kandungan TVB di bawah 20 mN% kecuali ikan cobia (28,94 mgN%). Kandungan TMA berkisar 6,09–11,81 mgN% dan TMAO 3,22–11,3 mgN% dan selama penyimpanan cenderung meningkat.
This review is directed at preventive health professionals, anatomic pathologists and technicians to focus their attention on the rapidly growing field of safe formalin practices. An updated overview ...of the most recent improvements in preventive measures versus formaldehyde (FA) in the anatomic pathology laboratories (APL) is provided. The occupational hygienist role and the required knowledge for a modern and clear occupational exposure assessment are described. Real-time, in-continuous, commercial analyzers for repeated FA exposure assessment are considered to evaluate technical changes in air monitoring programs, introduced to mitigate FA emissions, in compliance with the adopted limit values. To better choose the adequate instrumentation, the main features of each FA monitoring instrument recently introduced on the market are listed. Moreover, the main features of the modern workflow setting in APL are summarized. A computer-based scientific and non-scientific reports search by key-words was performed on PubMed, Web of Science, Google Scholar and Google Patents databases, querying the following topics: i) grossing workstation for ergonomic layout, ii) commercially available direct reading tools to measure formalin, iii) real-time, in-continuous FA monitoring instruments for sale. This review represents a useful tool to summarize the technical requirements and expert know-how necessary to minimize FA emissions and produce an exhaustive FA assessment in the APL.
Ovaj pregled usmjeren je na preventivne zdravstvene radnike, anatomske patologe i tehničare kako bi svoju pozornost usredotočili na brzo rastuće područje sigurnih formalinskih praksi. Ažurirani pregled nudi najnovija poboljšanja preventivnih mjera u odnosu na formaldehid (FA) u laboratorijima za anatomsku patologiju (APL). Opisana je uloga higijeničara na radu i potrebna znanja za modernu i jasnu procjenu izloženosti na radu. Komercijalni analizatori u stvarnom vremenu za kontinuiranu procjenu izloženosti FA razmatraju se za procjenu tehničkih promjena u programima praćenja zraka, uvedenim radi ublažavanja emisija FA, u skladu s prihvaćenim graničnim vrijednostima. Kako bi se bolje odabrala odgovarajuća instrumentacija, navedene su glavne značajke svakog instrumenta za praćenje FA koji je nedavno predstavljen na tržištu. Štoviše, sažete su glavne značajke suvremenih postavki tijeka rada u APL-u. Računalno zasnovano pretraživanje znanstvenih i neznanstvenih izvješća po ključnim riječima provedeno je u bazama podataka PubMed, Web of Science, Google Scholar i Google Patents, s težištem na sljedeće teme: i) prikupljanje radnih stanica za ergonomski raspored, ii) komercijalno dostupni alati za izravno očitanje mjerenja formalina, iii) instrumenti za kontinuirano praćenje FA u stvarnom vremenu u prodaji. Ovaj pregled predstavlja koristan alat za sažimanje tehničkih zahtjeva i stručnog znanja potrebnog za minimiziranje emisija FA i izradu iscrpne procjene FA u APL-u.
Sebagian besar wilayah Kalimantan Selatan adalah terdiri dari rawa-rawa. Salah satu tumbuhan rawa yang banyak tumbuh di daerah rawa Kalimantan Selatan adalah Purun Tikus (Eleocharis Dulcis). Sampai ...saat ini pemanfaatan purun tikus oleh masyarakat setempat hanya sebatas pembuatan tikar. Di lain pihak, kebutuhan akan papan sebagai bahan bangunan meningkat, seiring dengan tingginya permintaan konsumen akan suatu produk yang berbahan dasar kayu. Melihat dari potensi yang ada, diupayakan pemanfaatan purun tikus di daerah Kalimantan Selatan lebih dimaksimalkan. Dalam hal ini pemanfaatannya sebagai bahan matrik komposit dalam pembuatan papan partikel. Oleh karena itu penelitian ini berupaya manfaatankan purun tikus (Eleocharis dulcis) sebagai bahan substitusi bahan matrik komposit dan juga mengetahui pengaruh serat-serat purun tikus tersebut terhadap sifat fisis (kadar air dan kerapatan) dan sifat mekanik (keteguhan patah, kuat lentur). Untuk pengolahan papan partikel dibuat dua variasi susunan serat purun tikus, sampel A yaitu serat purun tikus dipotong kecil-kecil dan disusun secara acak pada cetakan, perlakuan B yaitu serat purun tikus dipotong memanjang dan menyamping di cetakan. Serat purun tikus yang sudah kering dipotong-potong sesuai dengan variasi serat. Filler berupa daun-daun akasia yang kering dan bersih dihaluskan menggunakan belender kemudian dicampurkan dengan urea formaldehid. Serat purun tikus dan filler dicetak pada cetakan berukuran 30 x 30 cm yang dipres panas pada suhu 800-900C. Produk yang dihasilkan berupa papan partikel yang akan diuji dan dianalisa sifat elastisitas dan keteguhan patahnya serta sifat kadar air dan kerapatannya yang akan dibandingkan terhadap standar SNI 03-2105-1996 dan JIS A 5908-2003. Hasil Pengujian Nilai Sifat fisik yaitu menunjukkan kadar air rata – rata 12,75 % dan kerapatan rata rata 0,84 g/cm3. Hasil pengujian sifat mekanik yaitu modulus elastisitas rata rata 10.750 Kg/cm2 dan modulus patah rata rata 80,5 Kg/cm2. Hasil Tersebut mendekati dan sudah sesuai dengan Standar SNI dan JIS dan papan partikel ini layak sebagai komposit
Formaldehyde resins are present in textile, leather and wood industries. Due to the harmful character of formaldehyde, different alternatives have been found to exclude or reduce its content on ...processed goods. However, the effect of dyestuffs on the formaldehyde content of goods containing formaldehyde-synthesized resins has not been studied up to date. The aim of this work is to check if the presence of free amino groups in the structure of dyestuffs exerts an influence on the formaldehyde content on leathers treated with formaldehyde-synthesized resins. Six dyes, belonging to three different families (acid dyes, direct dyes and basic dyes), have been taken as examples to evaluate how their structures affect the reaction with formaldehyde present in leather. The variation of the formaldehyde content in dyed leathers with respect to control samples (treated with resin only) and its evolution with time have been also considered.
It has been found that the ability of dyes in reducing the formaldehyde content in leather depends on the amount of amino groups amenable to reaction with formaldehyde. Those amino groups that in their vicinity have other functionalities, with which to form relatively stable structures, have a reduced reactivity with formaldehyde.
The reduction ability of dyes also depends on the formaldehyde content in leather. The lower the formaldehyde content is in the leather, the higher this reduction ability. Acid Black 234 dye caused a formaldehyde content reduction of approximately 84% in leathers treated with melamine-formaldehyde resin of low formaldehyde content in the analysis carried out after 90 days of leather processing whereas the reduction was approximately 20% when the resin was of high formaldehyde content.
The highest reduction ability of basic dyes corresponded to the dye that has the greatest amount of amino residues amenable to reaction with formaldehyde (Basic Orange 2). Basic Orange 2 dye exhibited higher reduction ability (90% of reduction in leathers treated with resin of high formaldehyde content after 90 days of leather processing) than the Acid Black 234 dye (approximately 20%), both containing similar amount of free amino residues. Thin layer chromatography analysis revealed that the Basic Orange 2 dye is mainly a single major component, while the Acid Black dye 234 is a mixture of components that can have a reduced reactivity with formaldehyde. Further experiments are required to investigate if the surface leather dyeing (Basic Orange 2 dye) have a higher influence on formaldehyde content reduction than the through-dyeing (Acid Black 234 dye).
•Amino groups in dye structure enable the formaldehyde content reduction.•The reduction depends on the reactivity of the amino groups with formaldehyde.•Hydroxyl and diazo groups close to the amino groups of a dye reduce this reactivity.•The greatest the amount of “free” amino groups, the highest the reduction ability.
Reakcija formoze – sveti gral kemičara Raos, Nenad
Kemija u industriji; časopis kemičara i tehnologa Jugoslavije,
4/2018, Letnik:
67, Številka:
3-4
Journal Article
Recenzirano
Odprti dostop
Već više od jednog i pol stoljeća bazna kondenzacija formaldehida u ugljikohidrate (reakcija formoze) plijeni pozornost kemičara u nadi da će dati homogene produkte i tako pronaći svoje mjesto u ...krilu kemijske tehnologije. U radu je opisano otkriće, istraživanje mehanizma, pokušaji optimalizacije te moguće primjene reakcije u regeneraciji ugljika na svemirskim stanicama. Prikazan je i njezin utjecaj na tumačenje fotosinteze (Baeyerova hipoteza) te postanka života na Zemlji.
Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna .
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