Synthesis of Macromonomers and Hyperbranched Polymers

2-Bis(hydroxymethyl) propionic acid 30.00 g (223.7 nunol), 2,2-dimethoxy-propane (41.4 mL, 335.4 mmol) and p-toluenesulfonic add monohydrate (2.10 g, 11.1 nunol) were dissolved in 100 mL of acetone. The mixture was stirred for 4 h at room temperature before 3.0 mL mixture of an ammonia solution (25 %) and EtOH (50/50, v/v)) was added into the reaction mixture to neutralize the catalyst. The solvent was removed by evaporation under reduced pressure at room temperature. The residue was then dissolved in CH2CI2 (600 mL) and extracted with two portions of water (80 mL). The organic phase was dried with anhydrous Na2S04 and evaporated to give (I) as white powder (33.0 g, 84 %). The H NMR spectra 

The general procedure employed was as follows. A three-necked flask equipped with a magnetic stirring bar and three rubber septum was chaiged with alkyne-(PSt-azide)2 macromonomer (2 g, 0.263 mmol), PMDETA (109.5 p,L, 0.526 mmol) and DMF (13.3 mL). The flask was degassed by four freeze-pump-thaw cycles, and then placed in a water bath thermostated at 35 °C. After 2 min, CuBr (75 mg, 0.526 nunol) was introduced to start the poly-condensation under N2 flow. Samples were taken at timed intervals and precipitated into a mixture of methanol/water (90/10, v/v) and the products were washed with excess methanol. After drying in a vacuum oven overnight at 40 °C, the resultant hyperbranched polystyrene was analyzed by SEC and LLS. 

The relative number- and weight-average molar masses (Mn,sEC and Mw.sec) and the absolute number- and weight-average molar masses (Mw.malls and 

For long polymer chains, i.e., (Rg) 1, the Berry plot is normally used. In static LLS, the scattering intensity was recorded at each angle three times and each time was averaged over 30 s. The scattering angle ranges from 12 to 120°. The refractive index increment of hyperbranched polystyrenes in toluene (dn/ dC = 0.111 mL/g at 25 °C and 633 nm) was determined by a precise differential refractometer. 

In dynamic LLS, the Laplace inversion of each measured intensity-intensity time correlation function (P q, t) in the self-beating mode can lead to a line-width 

---