ABS plastic recycling method
EPS plastic is a kind of general-purpose engineering plastics are widely used in electrical and electronic equipment components, auto parts and so on. Accordingly, after the retirement of these products, there is a lot of waste EPS plastic, because plastic is a thermoplastic ABS plastic, it has a recyclability. However, since the ABS regeneration occurs during the aging of service products, butadiene rubber phase partially oxidized in light and heat environment, a substantial decline in impact properties of the material. Therefore, the use of recycled ABS direct recovery is limited to a smaller range.
Improve the mechanical properties of ABS regeneration method, there are many, such as by adding a new ABS materials to restore the physical properties of recycled ABS, this method is only partially recycled ABS regeneration, regeneration ABS does not change the performance itself. Experts have found that modification of thermoplastic polyurethane blend of ABS and ABS in the TPU has good compatibility, because there are a NHCOO a TPU unit on the main chain, in which the ABS acrylonitrile units -CH2CH (CN) - It can form hydrogen bonds, and acrylonitrile units and TPU polyether or polyester soft segment there is a strong dipole-dipole effect, so we both have good compatibility. TPU is a thermoplastic elastomer as a toughener ABS reproduced, when the time is less than 15 parts amount of TPU, TPU can be uniformly dispersed in the continuous phase, ABS and TPU segments ABS entangled with each other, two mutually phase diffusion throughout, blends when subjected to an impact, the impact force to spread around by the rapid transfer segment intertwining elastomer caused a lot of crazes, the matrix is generated shear yield, by deformation blends inside and outside the well absorb impact energy, so that blends with a certain toughness, thereby preventing brittle fracture of materials, the macro is shown as notched impact strength. With the increase of the amount of TPU, recycled ABS / MFR TPU blends significantly increased flow performance is improved when the amount of TPU increases from 0 to 25 parts, MFR than the previous increase of 119% modified. This is mainly due to the linear block copolymer TPU belongs, hydrogen at a temperature in the ABS processing TPU molecules and between molecules is broken, reducing the intermolecular forces between the blend, much smaller than the apparent viscosity of ABS, such reproduction ABS / MFR TPU blend increases. When the TPU in an amount of 15 parts, the notched impact strength of the blend 13.3KJ / m2, compared to the previous modification increase by 26.7%, the tensile strength of 32.3MPa, than before the modification reduces 7.9%, a melt index of 6.1 g / (10min), than before the modification increase by 45.2%.
TPU-g-MAH graft enhance regeneration ABS performance (Grafted on the macromolecular chains are chemically bonded by means of an appropriate reaction branched or functional side groups, products formed as a graft copolymer graft copolymers decide on the composition of the main chain and branched , structure, length and number of branches. graft similar blend of long chain branching, branched short, large graft is similar to a random copolymer by copolymerization may be different polymers two properties grafted together to form a special performance of the graft. Thus, the graft-modified polymers, has become a simple and effective way to expand the application fields of polymer, a polymer material to improve performance such as EPS recycling. The use of maleic anhydride anhydride groups and thermoplastic polyurethane residual isocyanate (-NCO) groups react to form TPU-g-MAH graft, TPU-g-MAH graft maleic anhydride double key under the action of an initiator and regeneration of the residual double bond in the ABS graft reaction, increasing the compatibility of the elastomer TPU and the ABS between regeneration, regeneration improve the impact strength of ABS. TPU-g-MAH only can greatly increase the toughness of ABS reproduced, but also to improve the flow properties of the ABS reproduced. TPU-g-MAH is the anhydride groups in the TPU isocyanate -NCO group from chemical reactions, thereby reducing the TPU -NCO groups, reducing cross-linking between the TPU. ABS double and regeneration in MAH on TPU-g-MAH grafted in the double bond in the role of initiator DCP, and in situ formed at the interface (TPU-g-MAH) -g-ABS type graft reaction copolymers enhance the interfacial adhesion between the two phases to improve the interfacial adhesion.
TPU-g-MAH can be uniformly dispersed in the continuous phase in the ABS, ABS and TPU-g-MAH segment entangled with each other through two mutually phase diffusion, when blends impact force, the impact force generated by the chain entangled with each other rapid transfer segment to spread around, caused a lot of crazes elastomer matrix is generated shear yield, better absorb the impact by deformation blends inside and outside can make blends having a certain toughness to prevent brittle material fracture, the macro is shown as notched impact strength. With the increase of TPU-g-MAH content, the regeneration ABS / MFR TPU-g-MAH blends increases, when the TPU-g-MAH amount of from 0 to 25 parts, MFR increased by 50 over the previous modification %, less than the rate of increase to be added to the TPU, the main reason may be the TPU-g-MAH with ABS in the role of initiator DCP grafting reaction, the molecular weight of the blend increases, the interfacial adhesion between the two phases enhanced, MFR reduced. With the increase of TPU-g-MAH content, the regeneration ABS tensile strength decreased, TPU-g-MAH amount of from 0 to 25 parts, modified to reduce the tensile strength compared to the previous 9.1% notched impact strength and increase the tensile strength decreased, showing the typical characteristics of elastomer modified plastics. When the TPU-g-MAH in an amount of 20 parts, DCP in an amount of 0.5 part, the notched impact strength of the blend 20.2KJ / m2, compared to the previous 92.4% modified to improve the tensile strength of 32.8MPa, than change anterior decreased 6.6%, a melt index of 5.8g / (10min), modified to improve over the previous 38.1%. Thus when the TPU-g-MAH in an amount of 20 parts, DCP in an amount of 0.5 part, the regeneration of the best overall performance ABS.
