Dec. 27, 2018  90  US 2018/0373148 Al  added. The reactor was heated at 60°  C., whereupon reaction  ran for 15 hours. The reaction solution was poured into 1 L  of isopropyl alcohol for precipitation. The resulting white  solid was collected by filtration and vacuum dried at 60°  C.,  yielding Polymer 1 as white solid. The polymer was ana› lyzed for composition by $^{13}$C- and $^{1}$H-NMR and for Mw and  Mw/Mn by GPC, with the results shown below.  [0162]  Synthesis of Polymer 2  [0164]  Synthesis of Polymer 3  [0165]  A 2-L flask was charged with 7.8 g oftert-pentyl  methacrylate, 4.4 g of 3-oxo-2,7-dioxatricyclo[4.2.l.0 4 • 8 ]  nonan-9-yl methacrylate, 8.3 g of Monomer 3, 7.4 g of PAG  Monomer 1, and 40 g of THF as solvent. The reactor was  cooled at - 70° C. in nitrogen atmosphere, after which  vacuum pumping and nitrogen blow were repeated three  times. The reactor was warmed up to room temperature,  whereupon 1.2 g of AIBN as polymerization initiator was  added. The reactor was heated at 60°  C., whereupon reaction  ran for 15 hours. The reaction solution was poured into 1 L  of isopropyl alcohol for precipitation. The resulting white  solid was collected by filtration and vacuum dried at 60°  C.,  yielding Polymer 3 as white solid. The polymer was ana› lyzed for composition by $^{13}$C- and $^{1 }$H-NMR and for Mw and  Mw/Mn by GPC, with the results shown below.  [0163]  A 2-L flask was charged with 5.5 g of 1-methyl› cyclohexyl methacrylate, 3.1 g of 4-(1-methylcyclopenty› loxy)styrene, 4.4 g of 3-oxo-2,7-dioxatricyclo[4.2.l.0 4 • 8 ]  nonan-9-yl methacrylate, 6.7 g of Monomer 2, 11.0 g of  PAG Monomer 1, and 40 g ofTHF as solvent. The reactor  was cooled at - 70°  C. in nitrogen atmosphere, after which  vacuum pumping and nitrogen blow were repeated three  times. The reactor was warmed up to room temperature,  whereupon 1.2 g of AIBN as polymerization initiator was  added. The reactor was heated at 60°  C., whereupon reaction  ran for 15 hours. The reaction solution was poured into 1 L  of isopropyl alcohol for precipitation. The resulting white  solid was collected by filtration and vacuum dried at 60°  C.,  yielding Polymer 2 as white solid. The polymer was ana› lyzed for composition by $^{13}$C- and $^{1 }$H-NMR and for Mw and  Mw/Mn by GPC, with the results shown below.  Synthesis Example 2-3  Synthesis Example 2-2  Mw~9,700  Mw/Mn~ 1.83  Mw~ 8,300  Mw/Mn~ 1.77  ~  0  0  -0 $_{OH }$ Polymer 1  ~  0  0  ~Br  UOH  Polymer 2  r  o  o  I  o  o  {) D~  0  Polymer 3  o  o  o  o  r  0  0  r  ~  0  "’’YY"’  ~OH  Br 