中文摘要：

用PFI磨制备低游离度的杨木P-RCAPMP，并将其添加到高游离度杨木P—RCAPMP中获得混合浆，然后对混合浆成纸性能进行研究。首先研究了低游离度浆添加量对混合浆性能的影响，结果表明，随低游离度浆添加量的增加，纸张松厚度变化率下降，内结合强度变化率上升，抗张指数变化率先增加后降低且在添加量超过25％时达到最大值。这表明在高游离度浆中添加一定量的低游离度浆能改善混合浆成纸的强度性能。与未添加低游离度浆的浆料相比，当低游离度浆添加量为20％时，混合浆成纸松厚度得到改善，且强度性能相当。光学显微镜分析表明，随低游离度浆添加量的增加，丝状细小纤维是混合浆成纸强度性能提高的一个原因；SEM图与孔径分布研究表明，添加低游离度浆后，细小纤维能有效留在纸张中，填充在粗纤维孔隙中，进而提高纸张强度。

英文摘要：

The mixed pulp was prepared by adding low freeness pulp which was refined original P-RC APMP by PFI mill. The properties of the mixed pulp was studied by making handsheet with heating drying. The results indicated that with the amount increasing, the bulk decreased ; but the tensile and internal bond strength increased continuously when additive amount of low freeness pulp was less than 30%, it meant mixing certain amount of low freeness pulp could upgrade the paper strength. Comparison of the two drying modes, the mixed pulp dried in air was of advantage to bulk increase. With air drying, the mixed pulp containing 20% low freeness pulp could achieve higher bulk at the same strength. Observation of light microscope proved the fines of low freeness pulp were of benefit to the pulp strength. The SEM and PMI analysis showed that the mixed pulp and the control pulp had tile same average pore size diameter but the former had smaller maximum pore size diameter, which resulted to the higher bulk of the handsheet of the mixed pulp.