Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Victoria 3800, Australia.
Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Victoria 3800, Australia.
J Colloid Interface Sci. 2020 Sep 1;575:317-325. doi: 10.1016/j.jcis.2020.04.121. Epub 2020 Apr 29.
TiO-NPs-Cellulose composites functionality depends on the retention and dispersion of NPs in the composites. SAXS and SEM can be combined to reveal the effect PAE has on the NPs aggregation, retention and interaction mechanisms in the composites.
TiO-NPs-Cellulose sheets were made by first preparing PAE-cellulose suspensions of different PAE dosages (10 and 50 mg of PAE/g fibres). The TiO NPs suspension (at different NPs loading) was then added to the cellulose-PAE suspension. The final suspension was used to make flexible paper-like composites sheets. SEM and SAXS quantified NPs retention and aggregation state.
PAE dosage of 20 mg/g cellulose provides full surface coverage of cellulose fibres. A 10 mg of PAE/g cellulose covers half the cellulose surface area and no free PAE remains in the suspension. PAE dosage of 50 mg/g cellulose gives full cellulose surface coverage and provides a large amount of PAE (30 mg/g cellulose) free in the suspension. Surprisingly, at both PAE dosages, NP coagulates and the size of the aggregates increase with NPs loading. Aggregates of two particle sizes (10 and 35 nm) are formed and the number density of smaller particles is higher than larger particle. The NPs aggregates and their retention are similar at both PAE dosages, which is explained by different PAE-NPs bridging mechanisms.
TiO-NPs-纤维素复合材料的功能取决于 NPs 在复合材料中的保留和分散。小角 X 射线散射（SAXS）和扫描电子显微镜（SEM）可以结合使用，以揭示 PAE 对 NPs 在复合材料中的聚集、保留和相互作用机制的影响。
首先制备不同 PAE 用量（10 和 50 mg PAE/g 纤维）的 PAE-纤维素悬浮液，制备 TiO-NPs-纤维素片。然后将 TiO NPs 悬浮液（在不同 NPs 负载下）加入到纤维素-PAE 悬浮液中。最后将悬浮液用于制备柔性纸状复合材料片。SEM 和 SAXS 定量分析了 NPs 的保留和聚集状态。
PAE 用量为 20 mg/g 纤维素时，可完全覆盖纤维素纤维的表面。PAE 用量为 10 mg/g 纤维素时，覆盖了一半的纤维素表面积，且悬浮液中没有游离的 PAE。PAE 用量为 50 mg/g 纤维素时，纤维素表面完全被覆盖，并在悬浮液中提供了大量的游离 PAE（30 mg/g 纤维素）。令人惊讶的是，在这两种 PAE 用量下，NP 都会凝聚，且随着 NPs 负载的增加，聚集物的尺寸也会增大。形成了两种粒径（10 和 35nm）的聚集物，且较小颗粒的数密度高于较大颗粒。两种 PAE 用量下，NPs 的聚集物及其保留情况相似，这可以用不同的 PAE-NPs 桥接机制来解释。
