Prior to any DP measurement, the unbleached and semi-bleached samples were treated according to the Holocellulose procedure: 2 g of o.d. pulp were bleached with 20 mL of a sodium chlorite NaClO 2 solution (34 g/L), 20 mL of acetate buffer (pH 4.9) and 160 mL added DEI water within threaded cap bottle. The bottle was plunged in a water bath at 70 °C for 2h after vigorous shaking at t=0 and t=1h. Pulp was then washed thoroughly before storage or use. All the pulp samples containing "oxycellulose" ie. cellulose with substantial amounts of carbonyl groups introduced in the ZEo, H, Z alk E, and P 100C stages were first treated with sodium borohydride NaBH 4 . Sodium carbonate was added to reach pH 9, 1% NaBH 4 was introduced for 2 hours reacting at room temperature. The reduction was performed on 2 g of o.d. pulp in 250 mL Erlenmeyer with deionised water (PC = 2%) and under vigorous magnetic stirring. DPv was calculated using the formula established by Sihtola et al. after measuring pulp viscosity according to ISO 5351-1: DPv = 0.75 x (954 x log(ν) -325) 1.105 where ν is the viscosity of the pulp sample dissolved in cupriethylenediamine, expressed in mPa.s. Other DP values were calculated from the M w mass molar mass average obtained with Size Exclusion Chromatography (SEC) as: DPw=(M w -18.02)/(180.16-18.02). M n , M w , M z show, from left to right, an increased sensitivity towards high molar masses (Figure ) and can be used to calculate molecular dispersity Đ M . Đ M is generally defined as Đ M = M w /M n but can also be expressed as M z /M w ratio when looking at the high-M r fraction . In this work, as the focus was set on the cellulose fraction and especially the long cellulose chains, dispersity was calculated from the deconvoluted cellulose molar masses as