CA, CAB, CAP

Cellulose esters Cellulose acetate CA Cellulose acetate butyrate CAB Cellulose acetate propionate CAP also known as cellulose propionate CP Cellulose ethers Ethyl cellulose EC Benzyl cellulose. 

Dexel S (the S means that these grades are a direct equivalent of Cellidor S grades - formerly made by Bayer). 

Cellulose is a naturally occurring high polymer which cannot be injection molded unless it is modified by a combination of the following - 

Alkaline cellulose is reacted with ethyl chloride to form 

In general, cellulosics are hard, stiff materials which can be compounded with plasticizers to improve their flow, or ease of processing, and to improve the flexibility of finished moldings. They are extremely tough plastics and are reasonable electrical insulators but have high gas permeability and medium water vapor transmission rates. 

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ABA ABS ABS-PC ABS-PVC ACM ACS AES AMMA AN APET APP ASA BR BS CA CAB CAP CN CP CPE CPET CPP CPVC CR CTA DAM DAP DMT ECTFE EEA EMA EMAA EMAC EMPP EnBA EP EPM ESI EVA(C) EVOH FEP HDI HDPE HIPS HMDI IPI LDPE LLDPE MBS Acrylonitrile-butadiene-acrylate Acrylonitrile-butadiene-styrene copolymer Acrylonitrile-butadiene-styrene-polycarbonate alloy Acrylonitrile-butadiene-styrene-poly(vinyl chloride) alloy Acrylic acid ester rubber Acrylonitrile-chlorinated pe-styrene Acrylonitrile-ethylene-propylene-styrene Acrylonitrile-methyl methacrylate Acrylonitrile Amorphous polyethylene terephthalate Atactic polypropylene Acrylic-styrene-acrylonitrile Butadiene rubber Butadiene styrene rubber Cellulose acetate Cellulose acetate-butyrate Cellulose acetate-propionate Cellulose nitrate Cellulose propionate Chlorinated polyethylene Crystalline polyethylene terephthalate Cast polypropylene Chlorinated polyvinyl chloride Chloroprene rubber Cellulose triacetate Diallyl maleate Diallyl phthalate Terephthalic acid, dimethyl ester Ethylene-chlorotrifluoroethylene copolymer Ethylene-ethyl acrylate Ethylene-methyl acrylate Ethylene methacrylic acid Ethylene-methyl acrylate copolymer Elastomer modified polypropylene Ethylene normal butyl acrylate Epoxy resin, also ethylene-propylene Ethylene-propylene rubber Ethylene-styrene copolymers Polyethylene-vinyl acetate Polyethylene-vinyl alcohol copolymers Fluorinated ethylene-propylene copolymers Hexamethylene diisocyanate High-density polyethylene High-impact polystyrene Diisocyanato dicyclohexylmethane Isophorone diisocyanate Low-density polyethylene Linear low-density polyethylene Methacrylate-butadiene-styrene... 

In this group, there are acrylics, polymethylmethacrylate (PMMA) acrylonitrile butadiene styrene (ABS), aromatic polyamides (PI), cellulosics (CA, CAB, CAP, CN), ethylene vinyl acetate (EVA), fluoroplastics (Teflon, PTFE and FEP), Nylons - polyamides - (PA), polyacetals (POM), polyethylethylketone (PEEK), polybutene-1 (PB-1), polycarbonate (PC), polyesters - thermoplastic - (PETP, PBT, PET),... 

Cellulosic They are tough, transparent, hard or flexible natural polymers made from plant cellulose feedstock. With exposure to light, heat, weather and aging, they tend to dry out, deform, embrittle and lose gloss. Molding applications include tool handles, control knobs, eyeglass frames. Extrusion uses include blister packaging, toys, holiday decorations, etc. Cellulosic types, each with their specialty properties, include cellulose acetates (CAs), cellulose acetate butyrates (CABs), cellulose nitrates (CNs), cellulose propionate (CAPs), and ethyl celluloses (EC). 

Flow diagram of cellulose ester (acetates, CA, and mixed acetates with propionic or butyric acids, CAP or CAB) production. Note the introduction of water via dilute acid serves the purpose of reducing DS and raising solubility in organic solvents. (Adopted from Edgar [87])... 

From the Table, it can be seen that not many experimental data are actually available by comparison with calculated values, but mention should be made of the solubility parameter maps published for instance for HPMC [52], HPC [52], EC [52-55], CN [56,57], CA and CTA [53,56-58], CAB [56, 57] and CAP [58],... 

Dimethyl phthalate (DMP) also has high dissolving capacity for CN. It has good compatibility with cellulose esters and are used in celluloid made fi-om CN and plastic compounds or films made from other cellulosic polymers, cellulose acetate (CA), cellulose acetate-butyrate (CAB), cellulose acetate-propionate (CAP), and cellulose propionate (CP). It is light stable but highly volatile. Diethyl phthalate (DEP) possesses properties similar to DMP and is slightly less volatile. 

Therefore, in order to produce plastic moulding compounds with reasonable melt flow characteristics, as a rule, 15 to 35% plasticizer is added for CA and 3 to 25% for CAP and CAB [22]. In Figure 3.11 the melt flow index (MFI), as a measure of melt viscosity, is shown for typical cellulose ester moulding compounds as a function of plasticizer content. Obviously, as expected, the esters with longer side chains are more flexible and need considerably less plasticizer than the shorter chain esters to reach the same flowability at a given temperature. 

Cellulose acetate is the most important cellulose ester and various processing techniques for forming shaped bodies exist for this polymer. The mixed esters discussed above, CAP and CAB, are used predominantly for injection moulding applications in suitably plasticized form and are marketed as pellets. This is done for CA as well, but additionally, alternative processing routes are available where solution methods play an important role. This is in particular the case for fibre spinning and (thinner) film manufacture where cellulose diacetate (CDA) is dissolved in acetone and dry spun or solvent cast. Moreover, the traditional solventusing block process is employed for obtaining sophisticated, multicoloured thick sheets for applications like spectacle frames. 

Table 3.5 Typical properties of moulding compounds from cellulose acetate (CA), acetate propionate (CAP) and acetate butyrate (CAB) [52].

Cellulose acetate (CA), cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB) are thermoplastic materials produced through esterification of cellulose and are used for many packaging applications. Different raw materials such as cotton, recycled paper, wood cellulose, and sugarcane are used in the production of cellulose ester biopolymers in powder form. Such cellulose ester powders in the presence of different plasticizers and additives are extruded to produce various grades of commercial cellulose plastics. Recently, Misra et al. successfully used melt intercalation technique for the fabrication of cellulose nanocomposites and studied the effect of C30B on its performance characteristics [44]. From the study, the... 

Cellulose, whose repeat structure features three hydroxyl groups, reacts with organic acids, anhydrides, and acid chlorides to form esters. Plastics from these cellulose esters are extruded into film and sheet and are injection molded to form a wide variety of parts. Cellulose esters can also be compression molded and cast from solution to form a coating. The three most industrially important cellulose ester plastics are cellulose acetate (CA), cellulose acetate butyrate (CAB), and cellulose acetate propionate (CAP), with structures as shown in Fig. 2.2. 

The heat distortion temperatures of the cellulosic materials can overlap but the highest HDT is available from CAP this is followed by CAB and CA then by EC. Impact strength is roughly in the same order. 

These materials will absorb large amounts of water. CA will absorb up to 6% (usually 4.5%) water in 24 hours, CAB up to 2.2%, CAP up to 2.8% and EC up to 2%. This means that drying is often necessary. The temperature at which the material is dried is dependent upon the material s flow characteristics i.e. soft flow materials from 55 to 68 C (131 to 154 F) and... 

For general purpose grades the flow length for a 1mm (0.039in) wall section is approximately 300 1, but can reach 400 1 for easy flowing grades. CAB and CAP will flow into thinner wall sections than CA. 

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