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"Metode semi-Interpenetrating Polymer Network (semi-IPN) dapat digunakan untuk mensintesis hidrogel. Pada metode ini, jaringan kitosan terikat silang formaldehida akan berinteraksi dengan poli(N-vinil pirolidon) linear. Secara umum, rasio sweling dan derajat ikat silang hidrogel semi-IPN dipengaruhi oleh komposisi kitosan-PVP, konsentrasi formaldehida, dan waktu reaksi. Rasio swelling dan derajat ikat silang dari hidrogel kitosan-poli(N-vinil pirolidon) semi-IPN didapatkan sebesar 553,70% dan 58,82% pada rasio kitosan-poli(N-vinil pirolidon) 70:30 (%b/b), konsentrasi formaldehida 2% (%b/b), dan waktu reaksi 3 jam. Hidrogel kitosan-poli(N-vinil pirolidon) semi-IPN menunjukkan penurunan rasio swelling dan peningkatan derajat ikat silang dibandingkan hidrogel kitosan nonkovalen.

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Semi-Interpenetrating Polymer Network (semi-IPN) method was used to synthesize hydrogel. In this method, chitosan was crosslinked with formaldehyde and blended with Poly(N-vinyl pyrrolidone) to form crosslinked chitosan network that interracts with linear polymer of Poly(N-vinyl pyrrolidone). Generally, swelling ratio and degree of crosslinking of semi-IPN hydrogel were influenced by Poly(N-vinyl pyrrolidone) amount, concentration of formaldehyde, and reaction time. Swelling ratio and degree of crosslinking of semi-IPN hydrogel was obtained at 553,70% and 58,82% in the ratio of chitosan- Poly(N-vinyl pyrrolidone) 70:30 (%w/w), formaldehyde concentration of 2%, and 3 hours of reaction time. Semi-IPN hydrogel of chitosan-Poly(N-vinyl pyrrolidone) has lower swelling ratio and higher degree of crosslinking compared to hydrogel of chitosan."

"Metode semi-IPN (Interpenetrating Polymer Network) merupakan salah satu metode yang digunakan untuk mensintesis hidrogel superabsorben (HSA) kitosan dan poli(N-vinil-2-pirolidon) (PVP) atau kitosan-PVP. Pada metode semi-IPN, kitosan mengalami reaksi ikat silang dengan asetaldehida membentuk jaringan polimer kitosan terikat silang yang berinteraksi dengan polimer PVP linier. Hasil sintesis HSA kitosan-PVP semi-IPN diharapkan memiliki kekuatan mekanik dan kemampuan swelling yang baik. Kekuatan struktur ikat silang akan meningkat sampai mencapai titik optimum seiring bertambahnya waktu reaksi, konsentrasi agen pengikat silang dan pengaruh rasio kitosan-PVP. Kemampuan swelling HSA kitosan-PVP semi-IPN dengan kekuatan struktur ikat silang yang optimum didapat pada rasio kitosan/PVP 70:30 (b/b%) dengan konsentrasi asetaldehida 2 % dan waktu reaksi 3 jam. HSA kitosan-PVP semi-IPN optimum memberikan persen derajat ikat silang 55,9 % dan kemampuan swelling yang cukup tinggi yaitu 475,6 %. Karakterisasi HSA dilakukan dengan spektrofotometer Fourier Transform Infra Red (FTIR), analisis termal (DSC) dan analisis morfologi (SEM).

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Semi-IPN (Interpenetrating Polymer Network) is one method which can be used to synthesis the superabsorben hydrogel (HSA) of chitosan and poly (N-vinyl-2-pyrrolidone) (PVP) or HSA chitosan-PVP. In the semi-IPN method, chitosan crosslinked with acetaldehyde forming a crosslinked polymer network of chitosan which interacts with linier polymer of PVP. The result of synthesis between HSA chitosan ? PVP semi-IPN is expected to have a good mechanical strength and swelling capability. The strength of crosslinking structure will raise up to its optimum point along with the increase of reaction time, concentration of crosslinker and the influence of chitosan-PVP ratio. Swelling cability of HSA chitosan-PVP semi-IPN with optimum strength of crosslinking structure is obtained in the ratio of chitosan/PVP at 70:30 (w/w %) with 2% acetaldehyde concentration and 3 hours reaction time. The optimum HSA chitosan- PVP semi-IPN provides 55,9% degree of crosslinking and high enough swelling ability at 475,6%. Characterization of HSA is conducted by Fourier Transform Infra Red (FTIR) spectrometer, thermal analysis (DSC) and morphological analysis (SEM)."

"Metode IPN (Interpenetrating Polymer Network), baik semi maupun full-IPN, dapat digunakan untuk mensintesis hidrogel superabsorben (HSA) kitosan dan poli(N-vinil-2-pirolidon) (PVP) atau HSA kitosan-PVP. Pada semi-IPN kitosan diikat silang dengan asetaldehida membentuk jaringan polimer kitosan yang berinteraksi dengan polimer PVP linier. Sedangkan pada full-IPN jaringan polimer disintesis secara bertahap (sequential). Tahap pertama adalah sintesis jaringan polimer kitosan terikat silang asetaldehida dan homogenisasi dengan monomer N-vinil-2-pirolidon (NVP). Tahap kedua adalah sintesis jaringan polimer PVP terikat silang N, N’-metilenbisakrilamida (MBA) melalui polimerisasi radikal bebas monomer NVP dengan inisiator amonium persulfat (APS). Hasil sintesis HSA kitosan-PVP semi dan full-IPN memiliki kekuatan struktur ikat silang dan kemampuan swelling yang baik. Kekuatan struktur ikat silang meningkat dengan bertambahnya waktu reaksi, konsentrasi agen pengikat silang dan dipengaruhi rasio kitosan-PVP. Kemampuan swelling HSA kitosan-PVP dengan kekuatan struktur ikat silang yang baik didapat pada rasio kitosan/PVP 70:30 (b/b %) untuk semi-IPN atau rasio kitosan/monomer NVP 70:30 (b/b %) untuk full-IPN. HSA kitosan-PVP semi-IPN memberikan persen derajat ikat silang yang relatif rendah (39,0%) tetapi kemampuan swelling tinggi (496,9%). Sedangkan HSA kitosan-PVP full-IPN memberikan persen derajat ikat silang yang tinggi (76,5%) tetapi kemampuan swelling relatif rendah (116,9%). Karakterisasi dilakukan dengan spektrofotometer Fourier Transform Infra Red (FTIR), analisis termal (DSC) dan analisis morfologi (SEM).

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IPN (Interpenetrating Polymer Network) method, both semi-IPN and full-IPN can be used to synthesis the superabsorben hydrogel (HSA) of chitosan and poly(N-vynil-2-pyrrolidone) (PVP) or HSA chitosan-PVP. In the semi-IPN chitosan crosslinked with acetaldehyde was blended with PVP to form chitosan polymer network that interacts with linier polymer of PVP. While the full-IPN polymer network synthesized in stages (sequential method). The first stage is the synthesis of chitosan polymer network by crosslinked with acetaldehyde was homogenization with monomer N-vinyl-2-pyrrolidone (NVP). The second stage is the synthesis of PVP polymer network by crosslinked with N, N'-methylene bisacrylamide (MBA) through free radical polymerization of NVP monomer with the initiator ammonium persulfate (APS). HSA chitosan-PVP semi and full-IPN synthesized have a good strength of crosslinking structure and good swelling capability. The strength of crosslinking structure increased with the increase of reaction time, concentration of crosslinker and affected by chitosan-PVP ratio. Swelling ability of HSA chitosan-PVP with a good strength of crosslinking structure obtained in the ratio of chitosan/PVP 70:30 (w/w %) for semi-IPN or the ratio chitosan/NVP monomer 70:30 (w/w %) for full-IPN. HSA chitosan-PVP semi-IPN provides the degree of crosslinking is relatively low (39.0%) but higher swelling capacity (496.9%). Meanwhile HSA chitosan-PVP full-IPN provides higher degree of crosslinking (76.5%) but swelling capacity is relatively low (116.9%). Characterizations were done by fourier transform infra red spectrophotometer (FTIR), thermal analysis (DSC) and morphological analysis (SEM)."

"Metode semi interpentrating polymer network (semi-IPN) merupakan metode yang digunakan untuk mensintesis hidrogel kitosan-poliNNDMAA. Pada metode ini, jaringan kitosan akan terikat silang dengan agen ikat silang lalu berinteraksi dengan jaringan polimer NNDMAA secara linear. Hasil sintesis memperlihatkan bahwa variasi penambahan monomer NNDMAA, agen ikat silang dan waktu reaksi akan menurunkan daya swelling dan meningkatkan derajat ikat silang. Rasio swelling dan derajat ikat silang optimum hidrogel kitosan poli NNDMAA semi-IPN terikat silang formaldehida didapatkan sebesar 545,64% dan 75,02% pada penambahan 25% berat NNDMAA dan waktu optimum pada 2 jam. Hidrogel kitosan poli NNDMAA semi-IPN terikat silang formaldehida memilki derajat ikat silang yang lebih besar jika dibandingkan terikat silang glutaraldehida maupun asetaldehida. Karakterisasi dilakukan dengan spektrofotometer Fourier Transform Infra Red (FTIR), Differential Scanning Calotimetry(DSC) dan Scanning Electron Microscope (SEM).

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Method semi interpentrating polymer network (semi-IPN) is a method used to synthesize the chitosan hydrogel-poliNNDMAA. In this method, chitosan will crosslinked with a crosslink agent then interacts with the polymer network NNDMAA linearly. Synthesis results show that the variation of the addition of monomer NNDMAA, crosslink agents and reaction time will reduce swelling and increase the degree of crosslink. Swelling ratio and the degree of crosslink optimum chitosan hydrogel poly NNDMAA crosslinked semi-IPN formaldehyde obtained by 545.64% and 75.02% on addition of 25% by weight NNDMAA and optimum time at 2 hours. Chitosan hydrogel poly NNDMAA crosslinked semi-IPN formaldehyde have the degree of cross belt larger than glutaraldehyde cross-linked or acetaldehyde. Characterization is done by spectrophotometer Fourier Transform Infra Red (FTIR), Differential Scanning Calotimetry (DSC) and Scanning Electron Microscope (SEM)."

"Metode IPN (Interpenetrating Polymer Network) baik semi maupun full IPNdapat digunakan untuk mensintesis hidrogel superabsorben (HSA) kitosan dan poli(N-vinil-kaprolaktam) (PNVCL) atau HSA kitosan-PNVCL. Pada metode full IPN jaringan polimer disintesis secara bertahap (sequential). Tahap pertama adalah sintesis jaringan polimer kitosan terikat silang asetaldehida dan homogenisasi dengan monomer N-vinil-kaprolaktam (NVCL) Tahap kedua adalah sintesis jaringan polimer PNVCL terikat silang N Nmetilenbisakrilamida (MBA) melalui polimerisasi radikal bebas monomer NVCL dengan inisiator amonium persulfat (APS) Hasil sintesis HSA kitosan-PNVCL full-IPN memiliki kekuatan struktur ikat silang dan kemampuan swelling yang baik Kekuatan struktur ikat silang meningkat dengan bertambahnya waktu reaksi, konsentrasi agen pengikat silang, inisiator, dan dipengaruhi rasio kitosan-PNVCL Kemampuan swelling HSA kitosan-PNVCL dengan kekuatan struktur ikat silang yang baik didapat pada rasio kitosan/PNVCL 70:30 (b/b %). HSA kitosan-PNVCL full-IPN memberikan persen derajat ikat silang yang tinggi (78,2%) dan kemampuan swelling yang baik (390,2%) Karakterisasi.

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The IPN (Interpenetrating Polymer Network) method, both semi and full IPN, can be used to synthesize chitosan and poly (N-vinyl-caprolactam) (PNVCL) superabsorbent hydrogels or HSA chitosan-PNVCL. In the full method of IPN polymer networks are synthesized sequentially. The first stage is the synthesis of crosslinked acetaldehyde chitosan polymer tissue and homogenization with N-vinyl-caprolactam (NVCL) monomer The second stage is synthesis of PNVCL polymer network bound by N Nmetilenbisakrilamida (MBA) through NVCL monomer free polymerization with ammonium persulfate (APS) initiator Synthesis of HSA chitosan-PNVCL full-IPN has crosslinked structure strength and good swelling ability The strength of crosslinking structure increases with increasing reaction time, concentration of crosslinking agent, initiator, and influenced by chitosan-PNVCL ratio Swelling ability of HSA chitosan-PNVCL with good cross-link structure strength is obtained at the chitosan / PNVCL ratio of 70:30 (b / b%). Full-IPN HSA chitosan-PNVCL gives a high percentage of crosslinking (78.2%) and good swelling ability (390.2%) Characterization Characterization."

"Metode semi-Interpenetrating Polymer Network (Semi-IPN) merupakan salah satu metode untuk mensintesis hidrogel. Pada metode semi-IPN, kitosan mengalami ikat silang dengan agen pengikat silang asetaldehida/ formaldehida/ glutaraldehida membentuk jaringan polimer kitosan terikat silang yang kemudian berinteraksi dengan polimer metil selulosa yang berbentuk linier. Umumnya derajat ikat silang dan rasio swelling hidrogel semi-IPN akan dipengaruhi oleh waktu reaksi, rasio komposisi kitosan-metil selulosa, dan jenis agen pengikat silang yaitu asetaldehida, formaldehida, dan glutaraldehida. Kemampuan swelling dan derajat ikat silang hidrogel kitosan-metil selulosa semi-IPN yang optimum didapat pada rasio kitosan/metil selulosa 60:40 (b/b), agen pengikat silang formaldehida 2% (b/b), dan waktu reaksi 3 jam yaitu persen rasio swelling 785,6 % dan derajat ikat silang 50,8 %. Hidrogel kitosan-metil selulosa dengan metode semi-IPN memiliki rasio swelling dan derajat ikat silang lebih besar dibandingkan dengan hidrogel kitosan nonkovalen. Karakterisasi hidrogel kitosan-metil selulosa semi-IPN dilakukan dengan instrumen Fourier Transfrom Infra Red (FTIR), Differential Scanning Calorimetry (DSC), dan Scanning Electron Microscope (SEM).

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Semi-Interpenetrating Polymer Network (semi-IPN) method is one of many methods which used to synthesize hydrogels. In semi-IPN method, chitosan was crosslinked with crosslinking agent acetaldehyde/ formaldehyde/ glutaraldehyde to form crosslinked chitosan polymer network that will interracts with methyl cellulose polymer which have linear form. In general, degree of crosslinking and swelling ratio of semi-IPN hydrogels were influenced by reaction time, composition ratio of chitosan-methyl cellulose, and crosslinking agent acetaldehyde, formaldehyde, and glutaraldehyde. Swelling ability and degree of crosslinking of chitosan-methyl cellulose hydrogel with semi-IPN method optimally reach at chitosan/methyl cellulose ratio 60:40 (b/b) with formaldehyde crosslinking agent in 3 hours reaction time is 785,6 % swelling ratio and 50,8 % degree of crosslinking. Chitosan-methyl cellulose hydrogel with semi-IPN method has higher swelling ratio and degree of crosslinking compared to noncovalent chitosan hydrogel. Characterization of chitosan-methyl cellulose semi-IPN hydrogel using Fourier Transfrom Infra Red (FTIR), Differential Scanning Calorimetry (DSC), dan Scanning Electron Microscope (SEM) instrument."

"Salah satu bagian krusial pada investment casting ialah pembuatan cetakan keramik. Permasalahan yang terdapat pada cetakan keramik antara lain seringnya terjadi kegagalan saat proses penghilangan lilin, permeabilitas cetakan yang kurang, dan lamanya proses pengeringan lapisan slurry keramik. Untuk itu dilakukan penelitian pengaruh penambahan serat nilon (0, 10, 20 dan 30 gr/l) kedalam slurry cetakan keramik dengan tujuan mengetahui karakteristik cetakan dan produk cor akibat penambahan nilon pada slurry cetakan keramik. Karakterisasi pada sampel keramik berupa pengujian 3-point bending, sudut, porositas dan pengamatan SEM. Untuk produk cor sudu turbin, digunakan paduan Al - 9 wt.% Zn – 4 wt.% Mg – 3 wt.% Cu menggunakan cetakan keramik 20 gr/l nilon. Karakteristik produk cor berupa pengujian kekerasan dan pengamatan foto mikro serta SEM.Dari hasil pengujian didapat bahwa penambahan nilon akan meningkatkan ketebalan terutama pada bagian sudut cetakan keramik dan juga porositas pada cetakan keramik, sampel yang tidak diberi tambahan nilon (0 gr/l) memiliki kekuatan yang lebih baik dibandingkan sampel yang diberi tambahan nilon (10, 20 dan 30 gr/l) baik itu pada bagian rata (flat) maupun pada bagian sudut pada sebelum maupun sesudah pembakaran. Pada produk cor, nilai kekerasan menggunakan cetakan keramik berpenguat nilon lebih rendah dibanding tak berpenguat nilon dikarenakan kehadiran porositas pada produk cor.

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One of crucial part in investment casting is production of ceramic mould. The problems are found in the ceramic mould such us failure during wax removal, decrease of permeability and the long duration of drying process of the ceramic slurry coating. Following to this problems, the main discussion of this study was to analyse the effect of adding nylon fiber (0, 10, 20 and 30 gr/l) into ceramic slurry to the characteristics of mould and as cast product. Characterization of ceramic mould included 3-point bending testing, edge testing, porosity testing and SEM. For as cast product, the alloying element are Al – 9 wt.% Zn – 4 wt.% Mg – 3 wt.% Cu by ceramic mould with addition of 20 gr/l of nylon. Characterization of as cast product included hardness testing and observation of microstructure by optical microscope and SEM.

The results show that the addition of nylon increases the thickness of ceramic mould, mainly at the edges as well as increases the porosity. Samples with no addition of nylon (0 gr/l) have higher strength than samples with nylon (10, 20 and 30 gr/l) both on flat and edge for green and fired condition. The hardness of the as cast product made by using ceramic mould with the nylon addition, is lower. This is due to the presence of porosity in the product."

"Sintesis hidrogel kitosan-poli(N-vinil-2-pirolidon) (PNVP) dengan metode full-Interpenetrating Polymer Network (full-IPN) dilakukan secara bertahap (sequential). Tahap pertama yaitu melakukan sintesis jaringan polimer kitosan terikat silang asetaldehida melalui homogenisasi. Tahap kedua yaitu melakukan sintesis jaringan PNVP terikat silang N, N?-metilenbisakrilamida (MBA) melalui reaksi polimerisasi radikal bebas dari monomer NVP dengan agen pengikat silang MBA dan inisiator amonium persulfat (APS). Hidrogel kitosan-PNVP full-IPN yang dihasilkan, memiliki kekuatan ikat silang lebih baik yang teramati dari nilai derajat ikat silang serta dapat mempertahankan kemampuan swelling dengan baik yang teramati dari nilai rasio swelling dibandingkan dengan hidrogel kitosan.Hasil optimum dari rasio swelling dan derajat ikat silang pada hidrogel kitosan-PNVP full-IPN sebesar 149,8% dan 85,4% dengan komposisi kitosan:monomer NVP yaitu 70:30 (b/b %), waktu reaksi polimerisasi 0,5 jam, konsentrasi MBA 1% (b/b), serta konsentrasi APS 1% (b/b). Karakterisasi dilakukan dengan Spektrofotometer Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC), dan Scanning Electron Microscope (SEM).

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Synthesis of hydrogel chitosan-poly(N-vinyl-2-pyrrolidone) (PNVP) by full-Interpenetrating Polymer Network was performed in stages (sequential method). The first stage was the synthesis of chitosan polymer network by crosslinked with acetaldehyde under homogenization process. The second stage was the synthesis which was PNVP of crosslinked with N,N?-methylenebisacrylamide (MBA) through free radical polymerization reaction of NVP monomer, was used as the crosslink agent MBA and ammonium persulfate (APS) as the initiator. The synthesized hydrogel chitosan-PNVP full-IPN has a good strength due to the observed crosslinking structure observed the value of crosslinking degree and the good swelling capability by the value of swelling ratio compared with hydrogel chitosan.

The optimum result of swelling ratio and the degree of crosslinking from hydrogel chitosan-PNVP full-IPN were 149,8% and 85,4% which were obtained with the composition chitosan:NVP monomer of 70:30 (w/w %), the polymerization reaction time of 0,5 hours, the concentration MBA 1% (w/w), and the concentration APS 1% (w/w). Products characterizations were done by Fourier Transform Infrared Spectrophotometer (FTIR), Differential Scanning Calorimetry (DSC), dan Scanning Electron Microscope (SEM)."

"Material polimer untuk menyusun hidrogel harus dapat mengembang (swell) dan mempertahankan fraksi air pada strukturnya, namun tidak larut dalam air. Polimer alami memiliki gugus fungsi yang dapat menjadi pusat aktif reaksi dimana dapat dilakukan modifikasi untuk menghasilkan suatu polimer dengan karakteristik yang lebih baik. Kitosan merupakan polimer alami yang memiliki kekuatan struktur yang kurang dibandingkan kemampuan swelling. Sintesis hidrogel kitosan dengan metode full interpenetrating polymer network (IPN) dapat meningkatkan kekuatan struktur melalui ikat silang. Tahap pertama adalah sintesis jaringan polimer kitosan terikat silang asetaldehida. Tahap kedua adalah sintesis jaringan polimer PNVCL terikat silang N, N?-metilenbisakrilamida (MBA) melalui polimerisasi radikal bebas monomer NVCL dengan inisiator amonium persulfat (APS). Variasi waktu, rasio kitosan-PNVCL, konsentrasi agen pengikat silang, dan konsentrasi inisiator dipelajari untuk mengetahui kondisi optimum. Kondisi optimum diperoleh pada reaksi 2 jam dengan rasio kitosan/NVCL 90:10 (b/b %), konsentrasi MBA 0,5%, dan konsentrasi APS 3%. HSA kitosan-PNVCL memberikan rasio swelling 380,66% dan derajat ikat silang 60,85%. Karakterisasi HSA dilakukan dengan spektrofotometer Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric analysis (TGA), Scanning Electron Microscope (SEM), dan X-Ray Diffraction (XRD).

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Polymer material used for hydrogel should have the ability to swell and to keep water molecules in its structure without dissolving in water. Natural polymers has functional groups which can perform as active sites in modification to produce polymer with better characteristic. Chitosan is a natural polymer which has good swelling ability but lack of structural strength. Synthesis of chitosan hydrogel by interpenetrating polymer network (IPN) will increase its strength through crosslinking. In this research, the first step of modification was the synthesis of chitosan polymer network crosslinked by acetaldehyde. The next step was the synthesis of PNVCL polymer network crosslinked by N,N-methylbisacrylamide (MBA) through free radical polymerization of NVCL monomer with ammonium persulfat (APS) as the initiatior. Optimum reaction time, chitosan/PNVCL ratio (w/w %), concentration of crosslinker agent, and concentration of initiator had been observed. The optimum conditions were obtained as followed: 2 hours reaction, the ratio chitosan/PNVCL of 90:10 (w/w %), %-w MBA concentration of 0,5%, and APS concentration of 3%. The swelling ratio of the hydrogel was 380,66% while the crosslinking degree was 60,85%. Fourier transfor infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric analysis (TGA), Scanning Electron Microscope (SEM), and X-Ray diffraction (XRD) were used for the characterization of the hydrogel."

"Hidrogel semi-IPN merupakan suatu jaringan polimer yang memiliki kemampuan menyerap air yang besar dan cenderung mempertahankan strukturnya. Sintesis hidrogel kitosan-polistirena dengan metode semi-IPN dilakukan dengan dua tahap. Pada tahap pertama dibentuk jaringan kitosan terikat silang dengan menggunakan variasi agen pengikat silang yaitu, asetaldehida, formaldehida, dan glutaraldehida. Pada tahap kedua dilakukan polimerisasi polistirena di dalam jaringan kitosan terikat silang. Kondisi optimum dalam sintesis hidrogel kitosan-polistirena semi-IPN diperoleh dengan waktu reaksi polimerisasi polistirena selama 4 jam, komposisi kitosan dan stirena sebesar 80:20, dan agen pengikat silang asetaldehida. Pada kondisi optimum, hidrogel kitosan-polistirena semi-IPN memiliki sifat mekanik yang lebih baik dibandingkan dengan hidrogel kitosan dan mampu mempertahankan kemampuan swelling yang baik. Nilai rasio swelling dan derajat ikat silang hidrogel kitosan-polistirena semi-IPN pada kondisi optimum sebesar 751,2% dan 24,1% secara berurutan. Karakterisasi hidrogel kitosan-polistirena semi-IPN dilakukan dengan spektrofotometer Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC), dan Scanning Electron Microscope (SEM).

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Semi-IPN hydrogel is a polymer network that has a great ability to absorb water and tend to maintain its structure. Synthesis of hydrogel chitosan -polystyrene by semi-IPN method performed by two steps. First step, chitosan crosslinked network formed by using a variety of crosslinking agents, namely acetaldehyde, formaldehyde, and glutaraldehyde. In the second step, polymerization polystyrene in chitosan crosslinked network. The optimum conditions in synthesis of chitosan hydrogel-polystyrene semi-IPN is obtained with a reaction time of polymerization of polystyrene for 4 hours, composition of chitosan and styrene is 80:20, and the crosslinking agent is acetaldehyde. At the optimum conditions, hydrogel chitosan- polystyrene semi-IPN has better mechanical properties compared with the chitosan hydrogel and able to maintain good swelling capability. The value of swelling ratio and the degree of crosslinking of hydrogel chitosan-polystyrene semi-IPN in optimum condition are 751.2% and 24.1%. Characterization of hydrogel chitosan-polystyrene semi-IPN has been done by Spectrophotometer Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscope (SEM)."