Calcium Carbonate–Carboxymethyl Chitosan Hybrid Materials

Abstract

In the present work, precipitated calcium carbonate (PCC) and carboxymethyl chitosan (CMC) were prepared to obtain new hybrid materials used in papermaking. In the first step, occurred the precipitation of CaCO3 in solution containing CMC at different levels (0.5%, 1%, and 1.5%). In the second step, PCC–CMC hybrid material (25%) was added to pulp suspension, and the sheets were made. The effect of PCC–CMC on paper properties (mechanical and optical) was systematically investigated. Breaking length, the brightness and opacity of the sheets obtained with the PCC–CMC material were better than the sheets fabricated with the unmodified PCC at similar levels of content.

Effects of Hybrid Polymeric Material Based on Polycaprolactone on the Environment

“…The first (mineralization) consists of the decomposition of the organic substance under the action of soil microorganisms and the release of ammonium ions, and the second (immobilization) consists of the conversion of mineral nitrogen from the soil, also under the action of microorganisms, into cellular proteins and other compounds with organic nitrogen [ 34 ]. …”

Recent Advances in Stimulus-Responsive Nanocarriers for Pesticide Delivery

“…In contrast to light and temperature-based controlled release materials, which often face challenges in accurately releasing the active ingredient, pH-responsive materials offer the advantage of targeted and controlled release. − This capability stems from acidic and basic functional groups within the pH-responsive materials. − For instance, herbivorous Lepidopteran pests have alkaline guts that aid in digesting their target organisms and elevate the alkalinity of their surroundings. On the other hand, certain fungi, like Fusarium acnes , secrete organic acids during their growth and reproduction, which can degrade plant tissues and reduce environmental acidity. , Drawing from such insights, numerous researchers devised various pH-responsive carriers for pesticide loading.…”

Chitosan as a Canvas for Studies of Macromolecular Controls on CaCO3Biological Crystallization

“…This capability has motivated diverse investigations of how to synthesize derivatives for new and existing applications, but to our knowledge relatively few studies were directed at understanding the influence of their properties upon CaCO 3 formation (Table 5). Several of these studies explored the effects of carboxymethyl chitosan (CMCS)�chitosan functionalized with carboxyl groups to varying degrees (DS-(CM))�on the precipitation of CaCO 3 for applications as a bioadditive to paper 147 or as a scale inhibitor in oilbrines. 148,149 It is likely that a substantial motivation for these studies is the high solubility of CMCS in pure water, in contrast to most chitosans that require an acetic acid cosolvent.…”

“…This capability has motivated diverse investigations of how to synthesize derivatives for new and existing applications, but to our knowledge relatively few studies were directed at understanding the influence of their properties upon CaCO 3 formation (Table ). Several of these studies explored the effects of carboxymethyl chitosan (CMCS)chitosan functionalized with carboxyl groups to varying degrees (DS­(CM))on the precipitation of CaCO 3 for applications as a bioadditive to paper or as a scale inhibitor in oil-brines. , It is likely that a substantial motivation for these studies is the high solubility of CMCS in pure water, in contrast to most chitosans that require an acetic acid cosolvent. The findings generally support the notion that an increased concentration of CMCS in the nucleating system (regardless of DS­(CM)) leads to less stable polymorphs, often with unusual morphologies and decreased particle size. − Interpretations across (and sometimes within) the CMCS studies are impeded by the wide range of DS­(CM) that spanned 0.2 to 1.6.…”

“…Several of these studies explored the effects of carboxymethyl chitosan (CMCS)chitosan functionalized with carboxyl groups to varying degrees (DS­(CM))on the precipitation of CaCO 3 for applications as a bioadditive to paper or as a scale inhibitor in oil-brines. , It is likely that a substantial motivation for these studies is the high solubility of CMCS in pure water, in contrast to most chitosans that require an acetic acid cosolvent. The findings generally support the notion that an increased concentration of CMCS in the nucleating system (regardless of DS­(CM)) leads to less stable polymorphs, often with unusual morphologies and decreased particle size. − Interpretations across (and sometimes within) the CMCS studies are impeded by the wide range of DS­(CM) that spanned 0.2 to 1.6. Owing to this variability in composition and the inconsistent protocols, these studies provide little quantitative insight into how the composition of CMCS influences CaCO 3 nucleation.…”