Fabrication of Millable Polyurethane Elastomer/Eucommia Ulmoides Rubber Composites with Superior Sound Absorption Performance

Sound absorbing materials combining millable polyurethane elastomer (MPU) and eucommia ulmoides rubber (EUG) were successfully fabricated via a physical blending process of EUG and MPU. The microstructure, crystallization performances, damping, mechanical and sound absorption properties of the prepared MPU/EUG composites were investigated systematically. The microstructure surface of various MPU/EUG composites became rough and cracked by the gradual incorporation of EUG, resulting in a deteriorated compatibility between EUG and MPU. With the increase of EUG content, the storage modulus (E’) of various MPU/EUG composites increased in a temperature range of −50 °C to 40 °C and their loss factor (tanδ) decreased significantly, including a reduction of the tanδ of MPU/EUG (70/30) composites from 0.79 to 0.64. Specifically, the addition of EUG sharply improved the sound absorption performances of various MPU/EUG composites in a frequency range of 4.5 kHz–8 kHz. Compared with that of pure MPU, the sound absorption coefficient of the MPU/EUG (70/30) composite increased 52.2% at a pressure of 0.1 MPa and 16.8% at a pressure of 4 MPa, indicating its outstanding sound absorption properties.

Emerging Applications of Silica Nanoparticles as Multifunctional Modifiers for High Performance Polyester Composites

Nano-modification of polyester has become a research hotspot due to the growing demand for high-performance polyester. As a functional carrier, silica nanoparticles show large potential in improving crystalline properties, enhancing strength of polyester, and fabricating fluorescent polyester. Herein, we briefly traced the latest literature on synthesis of silica modifiers and the resultant polyester nanocomposites and presented a review. Firstly, we investigated synthesis approaches of silica nanoparticles for modifying polyester including sol-gel and reverse microemulsion technology, and their surface modification methods such as grafting silane coupling agent or polymer. Then, we summarized processing technics of silica-polyester nanocomposites, like physical blending, sol-gel processes, and in situ polymerization. Finally, we explored the application of silica nanoparticles in improving crystalline, mechanical, and fluorescent properties of composite materials. We hope the work provides a guideline for the readers working in the fields of silica nanoparticles as well as modifying polyester.

ZnO-Activated Carbon Blended as a Catalyst for Oxidative Desulfurization of Dibenzothiophene

The problem of sulfur content in heavy oil is a challenge for researchers to meet the needs of environmentally friendly fuels. The catalyst preparation plays an important role in the desulfurization process. The synthesis of ZnO-activated carbon as a catalyst and its activity in oxidative desulfurization (ODS) reaction has been successfully carried out. In this work, the ZnO and activated carbon (AC) were blended by a solid-solid reaction. The ZnO, AC, and ZnO-AC were then characterized using acidity test with pyridine vapor adsorption, Fourier Transform Infra-Red (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX), and Surface Area Analyzer (SAA). ODS of dibenzothiophene (DBT) reaction was performed by using H2O2 under variation of the reaction time (30, 60, 120, and 150 min) for the ZnO-AC catalyst. The efficiency of ODS-DBT was analyzed by a UV-Visible spectrophotometer. The XRD analysis result showed that ZnO-AC blended displays new crystal peaks of Zn in the AC diffractogram. The surface area (734.351 m2/g) and acidity (4.8780 mmol/g) of ZnO-AC were higher than ZnO and AC themselves. ZnO-AC produced the highest efficiency of ODS-DBT which was 93.83% in the reaction time of 120 min. Therefore, the simple procedure of this physical blending was proved effective to homogenize between ZnO and AC into ZnO-AC so that it has good physicochemical properties as an ODS-DBT catalyst. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Effect of Modifications in Poly (Lactide-co-Glycolide) (PLGA) on Drug Release and Degradation Characteristics: A Mini Review

The use of PLGA in the pharmaceutical industry has only increased as we move towards more and more advanced delivery carrier systems. The qualities of PLGA like biocompatibility, biodegradability and a tunable degradation and drug release has only helped in keeping up the release requirements desired for various delivery platforms. Fine-tuning the release and degradation rate is gaining more and more attention as researchers keep pushing the boundaries of novel delivery carriers. Various experiments are being performed to understand the degradation behavior drug of PLGA under various physiological and process-related conditions. The understanding of these parameters has helped formulate various ways one can fine-tune the properties that can lead to the release of active ingredients encapsulated within. Various techniques have been tried and tested including modifications like chemical modifications, physical blending and surface modifications and have found to be effective means of release modulation in delivery systems like parenteral, orals, topicals and tissue engineering scaffolds. In this review, all these experiments and implications thereon have been discussed in detail.

Membran Alginat Padina sp. - Polietilen Glikol (AP-PEG): Preparasi, Karakterisasi dan Aplikasinya sebagai Enkapsulan

<p>Pengembangan penelitian tentang material berbasiskan sumber daya alam lokal dan dapat diperbaharui terus dikembangkan akhir-akhir ini. Hal tersebut didasari adanya kebutuhan material baru dengan karakteristik yang lebih menguntungkan dan dapat digunakan pada aplikasi yang spesifik. Penelitian ini bertujuan untuk mempelajari preparasi membran alginat-polietilen glikol (AP-PEG) dan aplikasinya sebagai enkapsulan. Alginat yang digunakan adalah hasil ekstraksi dari rumput laut cokelat <em>Padina sp. </em>Dengan metode maserasi jalur asam alginat. Preparasi membrane alginat <em>Padina sp.</em>-polietilen glikol (AP-PEG) dilakukan dengan perbandingan PEG-AP = 1:5; 1:10; 1:15; 0:1 (b/b). Analisis gugus fungsi terhadap seluruh membran yang dihasilkan, menunjukkan bahwa membran AP-PEG yang dihasilkan diprediksi sebagai hasil <em>blending </em>secara fisika karena tidak ada gugus fungsi baru yang terbentuk. Membran dengan perbandingan berat PEG-AP=1:15 memiliki karakteristik terbaik dengan persentase <em>swelling </em>sebesar 1465,5%, <em>stress </em>sebesar 14,588 MPa, <em>strain </em>0,07 dan <em>Modulus Young </em>sebesar 193,13 MPa. Hasil analisis morfologi menunjukkan bahwa banyak rongga ditemukan pada membrane tersebut. Hasil uji disolusi terhadap membrane tersebut menunjukkan bahwa, pada pH 1,2 membran tersebut dapat melepaskan vitamin C sebesar 78,12% selama 60 menit dan tidak mengalami <em>cracking</em>. Di sisi lain, pada pH 7,2 membran tersebut dapat melepaskan vitamin C sebesar 83,54% dan <em>cracking </em>terjadi dalam waktu 12 menit. Hasil penelitian ini menunjukkan bahwa komposit AP-PEG dapat dibuat dari rumput laut coklat dan memiliki kemampuan sebagai enkapsulan. </p><p> </p><strong>Alginate <em>Padina sp.</em></strong>-<strong>Polyethylene Glycol (AP</strong>-<strong>PEG) Membranes: Preparation, Characterization and Their Application as Encapsulant</strong>. The development of research on materials based on local and renewable natural resources has been continuously being developed recently. This is based on the need for new materials with more favorable characteristics and can be used in specific applications. This research aims to study the synthesis of alginate-polyethylene glycol (AP-PEG) membranes and their application as an encapsulant. The alginate was extracted from the brown seaweed <em>Padina sp</em>. by maceration method using alginic acid pathway. Alginate <em>Padina sp.</em>-polyethylene glycol (AP-PEG) alginate membrane was prepared with a ratio of PEG:AP = 1: 5, 1:10, 1:15 and 0:1 (w/w). The functional group analysis showed that the resulting AP-PEG membranes were predicted as a result of physical blending due to no new functional groups are formed. The membrane with a weight ratio of PEG:AP = 1:15 had the best characteristics, with a percentage of swelling of 1465.5%, stress of 14.588 MPa, 0.07 strain, and Young Modulus of 193.13 MPa. Morphological analysis showed that the membrane obtained had many cavities. The dissolution test showed that the AP-PEG membrane was able to release vitamin C of 78.12% for 60 minutes at pH 1.2 and no cracking was observed, while at pH 7.2 the membrane was able to distribute vitamin C by 83.54% and cracking occurs within 12 minutes. The results of this study indicate that AP-PEG composites can be made from brown seaweed and have good encapsulant capabilities.