1515 hplc instrument

2,2’-azobisisobutyronitrile (AIBN) and pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) was purchased from Sigma-Aldrich Co. LLC. (St. Louis, MO, USA). Dipentaerythritol hexakis(3-mercaptopropionate) (DPEHMP) was purchased from TCI America (Montgomeryville, PA, USA). Methacryloxyethyl thiocarbamoyl rhodamine B was purchased from Polysciences (Warrington, PA, USA). Trifluoroacetic acid (TFA) and solvents were purchased from Thermo Fisher Scientific, Inc. (Waltham, MA, USA). tert-Butyl acrylate, methyl acrylate, and methyl mercaptopropionate (MMP) were purchased from Acros Organics (Morris County, NJ, USA). The inhibitors of these monomers were removed by passing through alumina before use. Other chemicals and solvents were used without further purification. 1H NMR was performed using a Varian MR400 (400 MHz, Agilent Scientific Instruments, Santa Clara, CA, USA) and analyzed using VNMRJ 3.2 (Agilent Scientific Instruments, Santa Clara, CA, USA) and MestReNova. Gel permeation chromatography (GPC) analysis was performed using a Waters 1515 HPLC instrument (Milford, MA, USA) using THF as an eluent, equipped with Waters Styragel (7.8 × 300 mm) HR 0.5, HR 1, and HR 4 columns in sequence and detected by a differential refractometer (RI). Sintered HAP discs (0.5 cm in diameter) were purchased from Himed, Inc. (Old Bethpage, NY, USA).