A series of soy-based copolyamides with different amino acid contents was synthesized by a condensation polymerization technique. The physical properties and enzymatic degradation properties were investigated. It was found that the introduction of amino acids into this type of copolyamide does not enhance the biodegradation ability but does improve the swelling properties of the copolyamides in water at a relative high pH and temperature.

ABSTRACT:To develop an easily deinkable toner for office copiers and laser printers, a series of homo-and copolyamide toner resins were synthesized via condensation polymerization of a soy-based dimer acid, 1,4-phenylenediamine, and L-tyrosine (an ␣-amino acid). The thermal properties of the resins were examined using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). It was found that the glass transition temperature (T g ), melting point (T m ), decomposition temperature (T d ), and crystallinity of the copolyamides were remarkably decreased as the content of L-tyrosine was increased. By using both homo-and copolyamides as binders, respectively, two dual-component toners were developed. The triboelectrical charge, particle size, and particle-size distribution of these toners were examined. The printing trials demonstrated that the images of the soy-based toners are similar to those of commercially available toners. However, because of the low crystallinity and high water-uptake ability of the amino acid-containing polyamide, the copolymer is swellable in an alkaline solution. Initial results from flotation deinking suggest that the amino acidcontaining toners are more easily deinked, likely due to their high swellability.

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The deformation behavior of wet lignocellulosic fibers was examined by applying a dilute suspension of dyed pulp fibers to a filter paper and then wet pressing the fibers onto glass slides. The geometry of single fiber crossing was determined using light interference and an image analysis computer program. The effects of pulp type, refining, wet pressing, drying and bleaching on the deformation behavior of pulp fibers were explored. The main effect of refining fibers was to reduce the step height for fiber-fiber crossings for both bleached and unbleached pulps by increasing the tendency of the cell wall to collapse and deform. All the pulps and treatments investigated maintained a relatively constant value for the step height/free span ratio.

A series of soy-based polyamides with different dimer acids and diamines were synthesized using a condensation polymerization technique. The molecular weight of polyamides prepared from 1,4-phenylenediamine increases greatly with a reaction temperature above 260ЊC. The physical properties of the polyamides, such as glass transition temperature ( T g ), melting point ( T m ), decomposition temperature ( T d ), crystalline behavior, and mechanical strength strongly depend on their molecular weight and flexibility of diamines used. The aromatic-based polyamides have a higher T g , T m , T d , and stronger mechanical strength than that of aliphatic-based polyamides. X-ray diffraction patterns of the samples indicate that all of the resins synthesized present a typical semicrystalline morphology. Polyamides made from hydrogenated dimer acid possess lower T g and higher mechanical strength, compared with polyamides from unsaturated dimer acid with different dimer and trimer ratios. These results are analyzed and discussed in accordance with the influence of rigid aromatic segments and the microstructure of different dimer acids.