pembelian polivinil alkohol

Polyvinyl alcohol (PVA) is a widely used synthetic material. PVA ability to dissolve in water and break down naturally makes it a good choice for packaging films. The main production methods for PVA film are aqueous solution coating and melt blow molding. PVA is hard to shape with heat because it melts at a higher temperature than it decomposes. This is due to the strong links between its molecules and its crystal structure. Therefore, the most important factor in the processing of PVA film is the selection of appropriate additives.   1. Effect of Plasticizer Amount on Tensile Strength, Tear Strength, and Elongation at Break of Polyvinyl Alcohol Film As shown in Figure 1, film ability to resist breaking lessens as more plasticizer is added. This suggests that plasticizers reduce how strong the film is. The plasticizer gel theory explains that when the plasticizer mixes with the resin, it loosens the points where the resin molecules connect. These connections have different strengths. The plasticizer pulls them apart and hides the forces that hold the polymer together. This reduces the secondary forces between the polymer macromolecules, increases the flexibility of the macromolecular chains, and accelerates the relaxation process. Tensile strength goes down as you add more plasticizer. As the amount of plasticizer is increased, the film becomes more flexible and stretches further before breaking. This suggests that plasticizers make the film more pliable. Plasticizers achieve this by weakening the attraction between the large molecules in the polymer. This increased flexibility and longer relaxation period lead to the film ability to stretch further. The data indicates that as more plasticizer is added, the film becomes easier to tear. This likely happens as the plasticizer reduces the film's surface energy and lessens the energy needed for both plastic flow and lasting deformation. These factors, in turn, contribute to the film's reduced resistance to tearing.   2. Effect of Crosslinker Amount on the Tensile Strength, Elongation at Break, and Tear Strength of PVA Film As shown in Figure 3, the film's tensile strength goes up gradually as the amount of crosslinker is increased, during which the elongation at break goes down gradually. When a certain point is reached, the film's tensile strength goes down gradually, while the elongation at break goes up gradually. At first, as more crosslinker is added, the number of working polymer chains goes up, intermolecular forces get stronger, and the polymer chains become less flexible. The ability of the large molecular chains to change shape and rearrange decreases while the chain relaxation is difficult. So, the tensile strength goes up, while the elongation at break goes down. Continuing the use of crosslinkers causes degradation and branching to increase gradually, which decreases the number of working polymer chains, and increases the flexibility of the polymer chains. The ability of the large molecular chains to change shape and rearrange increases, while the chain relaxation becomes easier. As a result, the tensile strength starts to go down again, while the elongation at break goes back up. As shown in Figure 4, the tear strength of the film changes with the amount of crosslinker. At first, it goes up, but then it starts to go down. This happens because when crosslinking starts, more crosslinker helps the polymer network form. This makes the film's surface energy go up gradually. It then needs more energy to spread plastic flow and irreversible viscoelastic processes. Because of this, the film's tear strength gets better as crosslinking happens. But, if there is too much crosslinker with too much polymer broken down, and there are more branching reactions, the tear strength gets worse.   3. Conclusions When you add more plasticizer, PVA film becomes less strong but stretches and tears more easily. When you add more crosslinker, film strength and resistance to tearing improve at first, but then weaken, while its ability to stretch keeps getting better.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Sarung tangan merupakan alat pelindung yang paling umum digunakan di laboratorium selain kacamata. Ada banyak jenis sarung tangan, dan setiap sarung tangan memiliki kegunaan yang berbeda-beda. 1. Karet alam (lateks)Sarung tangan lateks, yang terbuat dari karet alam, biasanya tidak memiliki lapisan dan tersedia dalam versi bersih dan steril. Sarung tangan ini dapat memberikan perlindungan yang efektif terhadap alkali, alkohol, dan berbagai larutan kimia encer, serta dapat mencegah korosi akibat aldehida dan keton dengan lebih baik. 2. Sarung tangan polivinil klorida (PVC)Sarung tangan ini tidak mengandung alergen, bebas bedak, memiliki produksi debu rendah, kandungan ion rendah, ketahanan korosi kimia yang kuat, dapat melindungi hampir semua zat kimia berbahaya, dan juga memiliki sifat antistatis. Permukaan yang ditebalkan dan dirawat (seperti permukaan bulu domba) juga dapat mencegah keausan mekanis umum, dan jenis yang ditebalkan juga dapat mencegah dingin, dengan suhu pengoperasian -4℃ hingga 66℃. Dapat digunakan di lingkungan bebas debu.Standar penilaian sarung tangan PVC:Produk Kelas A, tidak ada lubang di permukaan sarung tangan (sarung tangan PVC dengan bubuk), bubuk seragam, tidak ada bubuk yang terlihat, warna putih susu transparan, tidak ada noda tinta yang terlihat, tidak ada kotoran, dan ukuran serta sifat fisik setiap bagian memenuhi persyaratan pelanggan.Produk kelas B, noda sedikit, 3 bintik hitam kecil (1mm≤diameter≤2mm), atau sejumlah besar bintik hitam kecil (diameter≤1mm) (diameter> 5), deformasi, kotoran (diameter≤1mm), warna agak kuning, bekas paku serius, retakan, dan ukuran serta sifat fisik setiap bagian tidak memenuhi persyaratan. 3. Sarung tangan PESarung tangan PE adalah sarung tangan sekali pakai yang terbuat dari polietilena. Sarung tangan ini kedap air, kedap minyak, antibakteri, dan tahan terhadap asam dan basa. Catatan: Sarung tangan PE aman digunakan untuk makanan dan tidak beracun. Sebaiknya sarung tangan PVC dijauhkan dari makanan, terutama jika makanan panas. 4. Sarung tangan karet nitrilSarung tangan karet nitril biasanya dibagi menjadi sarung tangan sekali pakai, sarung tangan tanpa lapisan tugas sedang, dan sarung tangan berlapis tugas ringan. Sarung tangan ini dapat mencegah erosi oleh minyak (termasuk lemak hewani), xilena, polietilena, dan pelarut alifatik; sarung tangan ini juga dapat mencegah sebagian besar formulasi pestisida dan sering digunakan dalam penggunaan komponen biologis dan bahan kimia lainnya. Sarung tangan karet nitril tidak mengandung protein, senyawa amino, dan zat berbahaya lainnya, dan jarang menyebabkan alergi. Sarung tangan ini bebas silikon dan memiliki sifat antistatis tertentu, yang cocok untuk kebutuhan produksi industri elektronik. Sarung tangan ini memiliki residu kimia permukaan yang rendah, kandungan ion rendah, dan kandungan partikel kecil, serta cocok untuk lingkungan ruang bersih yang ketat. 5. Sarung tangan neoprenaMirip dengan kenyamanan karet alam, sarung tangan neoprene tahan terhadap cahaya, penuaan, kelenturan, asam dan alkali, ozon, pembakaran, panas dan minyak. 6. Sarung tangan karet butilKaret butil hanya digunakan sebagai bahan untuk sarung tangan tanpa lapisan berukuran sedang dan dapat digunakan untuk operasi di kotak sarung tangan, kotak anaerobik, inkubator, dan kotak operasi; memiliki daya tahan super terhadap asam fluorida, aqua regia, asam nitrat, asam kuat, alkali kuat, toluena, alkohol, dll., dan merupakan sarung tangan cairan sintetis karet khusus yang tahan. 7. Sarung tangan polivinil alkohol (PVA)Polivinil alkohol (PVA) dapat digunakan sebagai bahan untuk sarung tangan berlapis berukuran sedang, sehingga jenis sarung tangan ini dapat memberikan perlindungan tingkat tinggi dan ketahanan terhadap korosi terhadap berbagai bahan kimia organik, seperti hidrokarbon alifatik, aromatik, pelarut terklorinasi, fluorokarbon, dan sebagian besar keton (kecuali aseton), ester, dan eter. Situs web: www.elephchem.comWhatsapp: (+)86 13851435272Surel: admin@elephchem.com