Toluene

Natural rubber latex (NR; 60% dry rubber content with high ammonia) was obtained from Chemical and Materials Co., Ltd. (Bangkok, Thailand). Sodium dodecyl sulfate (SDS) and acrylamide (AM) monomer were purchased from Loba Chemie Pvt. Ltd. (Mumbai, India). Acrylic acid (AA) monomer and cumene hydroperoxide (CHP) initiator were obtained from Aldrich (St. Louis, MO, USA). AA was purified by using a column packed with alumina adsorbent before polymerization [24 (link)]. Tetraethylene pentamine (TEPA) activator was purchased from Acros organics (Geel, Belgium). Urea and toluene were purchased from RCI Labscan Limited (Bangkok, Thailand). Terric16A (10 wt%) and 1,3-diphenyl guanidine (DPG) were obtained from the Rubber Authority of Thailand (Bangkok, Thailand). Ethanol was purchased from Duksan Reagents (Ansan, South Korea). The compounding ingredients, such as zinc oxide (ZnO), stearic acid, N-cyclohexyl-2-benzothiazole sulfenamide (CBS), and sulfur, were received from Chemical Innovation Co., Ltd. (Bangkok, Thailand). Precipitated silica (JS-185, surface area (BET) of 170–200 m²/g, a DBP absorption value of 2.0–2.6 cm³/g, and a residue from a 75 µm sieve ≤ 10%) was obtained from Jinsha Precipitated Silica Manufacturing Co., Ltd. (Fujian, China). Silica was used without further purification. Deionized water was used throughout the study.

Fresh NR latex was generously provided by Thai Rubber Latex Corporation (Bangphli, Samutprakan, Thailand) Public Company Limited. Hollow borosilicate glass beads (HGBs) with an average diameter of 7 mm were made by the glassmaker shop. H₂O₂ (30% w/w), urea, and sodium dodecyl sulfate (SDS) were purchased from British Drug Houses (BDH Chemicals). Tetrapropyl orthotitanate was purchased from Fluka. Toluene, methanol, acetone, and tetrahydrofuran were purchased from RCI Labscan Limited. All chemicals were used without further purification.

Fresh NR latex was generously provided by Thai Rubber Latex Corporation (Bangphli, Samutprakan, Thailand) Public Company Limited. Hollow borosilicate glass beads (HGBs) with an average diameter of 7 mm were made by the glassmaker shop. H₂O₂ (30% w/w), urea, and sodium dodecyl sulfate (SDS) were purchased from British Drug Houses (BDH Chemicals). Tetrapropyl orthotitanate was purchased from Fluka. Toluene, methanol, acetone, and tetrahydrofuran were purchased from RCI Labscan Limited. All chemicals were used without further purification.

Commercial cellulose from cotton was purchased from Chanjao Longevity Co., Ltd. (Bangkok, Thailand). Potassium hydroxide (KOH, 85%) was procured from Sigma Aldrich Co. (St Louis, MO, USA). Toluene (99.8%) and ethanol (C₂H₆O, 95%) were attained from RCI Labscan Co., Ltd. (Bangkok, Thailand). Sodium chlorite (NaClO₂, 80%) was bought from Ajax Finechem Pty Ltd. (Scoresby VIC 3179, Australia). Acetic acid glacial (CH₃COOH, 99.7%) was purchased from QRëC™ (Auckland, New Zealand). All the materials and chemicals used in our study were of analytical grade.

Methanol (p.a.) was purchased from VWR International AB. Ethanol (>99.5%) was purchased from Solveco AB. Toluene (HPLC grade, >99.8%) was purchased from RCI Labscan. Chloroform (≥99.8%), lithium chloride (≥99%), potassium hydroxide, sulfuric acid (95–97%), acetic acid glacial (100%), dichloromethane (anhydrous, stabilized with amylene, ≥99.8%), acetic anhydride (p.a., >99.5%), pyridine (>99.5%), anisaldehyde (4-methoxybenzaldehyde, for synthesis), and resorcinol were purchased from Sigma-Aldrich, Merck KGaA (Darmstadt, Germany). Silica gel S (particle size: 32–63 μm, 230–400 mesh ASTM) were purchased from Riedel-de Haën. DEAE-cellulose 23 was purchased from Whatman. Polyisobutylmethacrylate was purchased from Sigma-Aldrich. Deionized water (Milli Q) was prepared with Purelab Flex 2 water purification system (AB Ninolab) and all organic solvents were redistilled prior to use.