Synthesis, characterization and Stydy thermal stabilization effect of calcium complex of anthocyanin on the poly (vinyl chloride)

In this study, calcium complex of anthocyanin was synthesized from anthocyanin, a flavonoid type natural phenolic product, which was extracted from eggplant peel. The structure of Ca-anthocyanin was characterized by FTIR spectroscopy. Its efficiency as bio-based thermal stabilizer to stabilize poly (vinyl chloride) was investigated and compared to that of Reapak B-NT/7060, a Ca/Zn-based commercial stabilizer. The influence of Ca-anthocyanin complex on the thermal degradation reaction of PVC was monitored by differential scanning calorimetry (DSC). The results indicated that the Ca-anthocyanin complex is an efficient thermal stabilizer and it reduces the rate of dehydrochlorination reaction of PVC already at a concentration as small as 2 phr, part per hundred of PVC resin. The thermal degradation reaction of PVC through the first degradation stage is clearly limited by the addition of Ca-anthocyanin complex as single (primary) stabilizer. Its efficiency is similar to that of Reapak B-NT/7060 used as reference stabilizer and it can enhance the performance of commercial stabilizer when used as co-stabilizer at mixing ratio (1:1). This study has allowed verifying and validating the usefulness of environmental friendly thermal stabilizer for PVC with very evident stabilization effect.

Green Secondary Plasticizer/Thermal Stabilizer in PVC Processing

Replacing 10 php DOP plasticizer by ESO has slightly increased tensile properties of PVC. A variety of media were used to study the leaching property of PVC and the results showed that the presence of ESO as a secondary plasticizer improved the leaching characteristic. There was slight difference in the hardness of the PVC samples with and without the ESO. In general, the PVC material became softer when DOP was partly replaced by ESO. The hardness of both samples became smaller after soaking in water, 30 wt.% acetic and 10 wt.% KOH solution and much bigger in other media. After immersion in n-hexane, the 60/0 sample blistered and became very hard, while the hardness of 50/10 sample increased only 12%. The morphology of fractured surface of the samples after soaking in n-hexane has clearly demonstrated this result. The replacing 10 php DOP by ESO has been also improved remarkably migration characteristic, thermal properties, and movement and volatilization in hot air. That means, ESO could be used as a secondary plasticizer/thermal stabilizer in PVC formulation.

Sintesis Dimerkaptoetil Adipat sebagai Bahan Baku Stabiliser Termal Polivinil Klorida berbasis Timah Organik Ester Balik

This research aimed to study the synthesis of dimercaptoethyl adipate as raw materials for polyvinyl chloride thermal stabilizer from mercaptoethanol and adipic acid in a batch reactor in which water as a side product was removed by azeotropic evaporation. The study was done through comparative experimental tests where the factors studied included entrainer, mercaptoethanol excess, and reactor volume. It was found that the products obtained were liquid at room condition having clarity in the 95%-99% range, sulfhydryl content in the 23.3%-24.3% range, and yield in the 83.7%-92.1% range. Clarities, sulfhydryl contents, and yields at 20% and 40% mercaptoethanol excesses were not significantly different. At 1 L and 5 L reactor volumes, sulfhydryl contents were found to be significantly different but clarities and yields were not significantly different. Both n-hexane and cyclohexane could be used as entrainers to remove water in the synthesis of dimercaptoethyl adipate. Both entrainers gave clarities and yields that are not significantly different. n-hexane resulted in sulfhydryl content which was 0.77% higher than that of cyclohexane. However, bearing in mind health factors, cyclohexane is considered to be better than n-hexane.

Sintesis Merkaptoetil Karboksilat sebagai Bahan Baku Stabiliser Termal Polivinil Klorida: Variasi Sumber Asam Lemak

Abstrak. Merkaptoetil karboksilat merupakan bahan baku stabiliser termal polivinil klorida atau polyvinyl chloride (PVC) berbasis timah organik. Stabiliser termal perlu ditambahkan ke dalam resin PVC sebelum diekstrusi untuk mencegah kerusakan karena pengerjaan panas. Stabiliser termal PVC dari timah organik dikenal sangat efektif, khususnya untuk aplikasi PVC kaku seperti pipa dan bingkai jendela. Penelitian ini bertujuan mengevaluasi sintesis merkaptoetil karboksilat dari asam lemak dan merkapto etanol dengan variasi sumber asam lemak yang meliputi asam lemak sawit, dedak padi dan biji kapuk. Percobaan dilakukan dalam sebuah reaktor partaian (batch) dengan asam kuat sebagai katalis. Percobaan dilakukan pada temperatur 60-80°C dan ekses merkapto etanol 10%. Kinerja sintesis dievaluasi melalui pengukuran kadar gugus merkaptan dan angka asam dalam produk serta perolehan produk. Pada rentang temperatur 60-80°C, ketiga asam lemak memberikan produk dengan kadar merkaptan pada rentang 6,4-7,8%. Temperatur 70°C merupakan temperatur terbaik karena menghasilkan produk dengan kadar merkaptan tertinggi tanpa memadat selama penyimpanan. Pada temperatur ini, produk memiliki angka asam pada rentang 11-41 mg KOH/g dan perolehan pada rentang 70-81%. Ketiga sumber asam lemak memberikan produk dengan kadar merkaptan yang mencukupi untuk dapat digunakan sebagai bahan baku stabiliser PVC. Mempertimbangkan kualitas produk dan ketersediaan di pasaran, distilat asam lemak sawit dipandang sebagai bahan baku yang paling baik. Kata kunci: asam lemak, merkaptoetil karboksilat, polivinil klorida, stabiliser termal. Abstract. Synthesis of Mercaptoethyl Carboxylate as Raw Materials for Polyvinyl Chloride Thermal Stabilizer: Variation in Fatty Acid Source. Mercaptoethyl carboxylate is a raw material for organotin-based polyvinyl chloride (PVC) thermal stabilizer. Thermal stabilizers need to be added to the PVC resin before extruded to prevent degradation due to heat treatment. Organotin PVC stabilizers are known to be very effective, especially for rigid PVC applications such as pipes and frames. This study was aimed to evaluate the synthesis of mercaptoethyl carboxylate from fatty acids and mercaptoethanol with various sources of fatty acids including palm, rice bran and kapok seed fatty acids. The experiment was carried out in a batch reactor with a strong acid as a catalyst. The experiments were conducted at 60-80°C and 10% mercapto ethanol excess. The performance of synthesis was evaluated by measuring mercaptan and acid contents and yield. In the range of 60-80°C, all three fatty acids provided products with mercaptan levels in the range of 6.4-7.8%. A temperature of 70°C is the best temperature as it gave a product with the highest mercaptan content without solidification during storage. At this temperature, the product had acid values in the range 11-41 mg KOH/g and yields in the range of 70-81%. Considering product quality and availability in the market, palm fatty acid distillate was seen as the best raw material. Keywords: fatty acid, mercaptoethyl carboxylate, polyvinyl chloride, thermal stabilizer. Graphical Abstract

Thermal Stabilization of Polyoxymethylene by PEG-Functionalized Hydroxyapatite: Examining the Effects of Reduced Formaldehyde Release and Enhanced Bioactivity

Nanostructured hydroxyapatite (HA) functionalized with poly(ethylene glycol) (HA-g-PEG) of different molar mass was used as a thermal stabilizer to prepare polyoxymethylene (POM) composites by a melt processing method. The chemical and crystalline structure of (HA-g-PEG) and POM/HA-g-PEG composites was investigated by means of FTIR and XRD. The thermal properties, degree of crystallinity, and melting behaviour of POM-based composites were analysed with TG, DSC, and TOPEM DSC methods. The tensile strength, Young’s modulus, toughness, and wettability of POM were investigated as well. A preliminary assessment of bioactivity, in vitro chemical stability, and formaldehyde release from POM/HA-g-PEG composites by Schiff’s test was also performed. An SEM/EDX method was used to observe the morphology of POM/HA-g-PEG composites. The results indicate that the addition of 1% HA-g-PEG slightly increases the melting temperature and degree of crystallinity. In small amounts, HA-g-PEG particles probably act as nucleating agents for the POM crystallization process. Incorporation of 5% HA-g-PEG to POM caused a decrease in the crystallinity of the polymer matrix, as a result, some mechanical properties of POM/HA-g-PEG composites also decreased. The thermal stability of POM/HA-g-PEG composites improved significantly from 309°C for unmodified POM to 342°C for POM/10.0% HA-g-PEG 600. The most effective thermal stabilizer was synthesized with the lowest mass-average molar mass PEG. The in vitro bioactivity test confirmed that, as the average molar mass of PEG in HA-g-PEG hybrids increased, POM-based composites indicated higher bioactivity. The in vitro chemical stability analysis results showed that both the POM matrix and the HA-g-PEG additive remain stable during the whole incubation time. Importantly, after seven days of dynamic incubation, no formaldehyde was detected in all filtrates, which is crucial in biomedical applications, among others.