Acrylic homopolymer property

The properties of alkyl acrylate homopolymers vary accordingly to the number of carbon atoms in the alkyl radical. As the number of carbon atoms increases the Tg decreases from room temperature to well below 0 °C until the number exceeds 10. However, as the carbons in the side chain increase oil resistance decreases. When carbon atoms in the alkyl radical are replaced by oxygen, oil resistance improves. 

Alkyl a-acetoxyacrylate intermediates were prepared by condensing pyruvate derivatives with acetic anhydride and then free radically converting them into the corresponding homo- or copolymers. All copolymers had thermal properties that were superior to that of polymethyl methacrylate. In addition poly(ethyl a-acetoxy-acrylate) homopolymers were injection moldable at 250°C. 

The stracture-property correlation of different copolymers with n-butyl acrylate and isobomyl acrylate units have been studied. The primary goal was to compare thermomechanical properties of block, gradient and statistical copolymers of nBA and IBA with various acrylate homopolymers (Scheme 1). The choice of nBA and IBA was dictated by very different thermal properties of the resulting homopolymers, glass transition temperature (Tg) of PnBA is -54°C while the Tg of PIBA is 94°C. Thus, their copolymerization with carefully selected ratios should result in polymers with thermal properties, i.e., Tg similar to acrylate homopolymers poly(t-butyl acrylate) (PtBA), poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA) and poly(n-propyl acrylate) (PPA). 

Statistical copolymers of uBA and IBA with different molecular weights and compositions were synthesized under ATRP conditions, as described in detail earlier (26). In all ATRP reactions, a CuBr/PMDETA complex was used since it is commercially available and well mediates controlled polymerization of acrylate monomers. Polymerizations were performed at 50°C in acetone/anisole mixture using EtBrIB as the initiator. The schematic representation of all prepared materials is shown in Scheme 2. The solid line represents a series of polymers with similar DP but systematically increasing IBA content. Another such group of copolymers is indicated with a dashed line. Copolymers with similar IBA/nBA ratio but different degree of polymerization (DP), i.e., the dotted line, were also synthesized. When comparing the thermo-mechanical properties of acrylate homopolymers and P(IBA-co-nBA) copolymers, the first important question is whether the copolymer system is isotropic in the bulk state or rather exhibits a micro-phase separation. To answer this question, the DSC thermograms for all samples shown in Scheme 2 were measured. 

A considerable amount of work has focused on the design and synthesis of macromolecules for use as emulsifiers for lipophilic materials and as polymeric stabilizers for the colloidal dispersion of lipophilic, hydrocarbon polymers in compressed CO2. It has been shown that fluorinated acrylate homopolymers, such as PFOA, are effective amphiphiles as they possess a lipophilic acrylate-like backbone and C02-philic, fluorinated side chains, as indicated in Figure 4.5-1 [100]. Furthermore, it has been demonstrated that a homopolymer which is physically adsorbed to the surface of a polymer colloid precludes coagulation due to the presence of loops and tails [110]. These fluorinated acrylate homopolymers can be synthesized homogeneously in CO2 as described in an earlier section. The solution properties [111,112] and phase behavior [45] of PFOA in SCCO2 have been thoroughly examined. Additionally, the backbone of these materials can be made more lipophilic in nature by incorporating other monomers to make random copolymers [34]. 

Angiolini L, Caretti D, Carlini C, SalateUi E. 1995. Optically active polymers bearing side chain photochromic moieties synthesis and chiroptical properties of methacrylic and acrylic homopolymers with pendant l lactic acid or l alanine residues connected to trans 4 aminoazobenzene. Macromol Chem Phys 196(9) 2737 2750. 

As fluorinated poly(alkylacrylates) have proved to be highly soluble in compressed CO2, they present themselves as possible components in the stabilization of heterogeneous reaction systems in CO2. Indeed, there has been considerable effort in the development and synthesis of polymeric emulsifiers for lipophilic materials and stabilizers for hydrocarbon polymer dispersions in CO2. DeSimone and coworkers demonstrated the feasibility of using fluorinated alkyl acrylate homopolymers, such as PFOA, as efficient amphiphiles, owing to the lipophilic acrylate backbone and the C02-philic fluorinated pendant chains [35, 36]. As was described earlier, these fluorinated alkyl acrylates are readily synthesized homogeneously in CO2. The solution properties and phase behavior of PFOA in compressed CO2 have been thoroughly examined and reported elsewhere [37-39]. 

Acrylic homopolymers [(—CH2CH(COOR)—) ] and copolymers are synthesized from acrylates and methacrylates. Through copolymerization, the polymer properties are widely varied from soft, flexible elastomers to hard, stiff thermoplastics and thermosets. Acrylic polymers are produced in many different forms including sheet, rod, tube, pellets, beads, film, solutions, lattices, and reactive syrups. 

Acrylonitrile (AN), C H N, first became an important polymeric building block in the 1940s. Although it had been discovered in 1893 (1), its unique properties were not realized until the development of nitrile mbbers during World War II (see Elastomers, synthetic, nitrile rubber) and the discovery of solvents for the homopolymer with resultant fiber appHcations (see Fibers, acrylic) for textiles and carbon fibers. As a comonomer, acrylonitrile (qv) contributes hardness, rigidity, solvent and light resistance, gas impermeabiUty, and the abiUty to orient. These properties have led to many copolymer apphcation developments since 1950. 

The earliest study describing vulcanised polymers of esters of acryUc acid was carried out in Germany by Rohm (2) before World War I. The first commercial acryUc elastomers were produced in the United States in the 1940s (3—5). They were homopolymers and copolymers of ethyl acrylate and other alkyl acrylates, with a preference for poly(ethyl acrylate) [9003-32-17, due to its superior balance of properties. The main drawback of these products was the vulcanisation. The fully saturated chemical stmcture of the polymeric backbone in fact is inactive toward the classical accelerators and curing systems. As a consequence they requited the use of aggressive and not versatile compounds such as strong bases, eg, sodium metasiUcate pentahydrate. To overcome this limitation, monomers containing a reactive moiety were incorporated in the polymer backbone by copolymerisation with the usual alkyl acrylates. 

Mixtures of monomers can be used to balance properties. This is possible due to the ease of copolymer formation via free-radical polymerization. The glass transition temperature of acrylic copolymers can be predicted from the weight fraction of the component monomers and the glass transition temperatures of the respective homopolymers [20]. Eq. 3 (commonly known as the Fox equation) is reported ... 

In a partially crystalline homopolymer, nylon 6, property enhancement has been achieved by blending with a poly(ethylene-co-acrylic acid) or its salt form ionomer [24]. Both additives proved to be effective impact modifiers for nylon 6. For the blends of the acid copolymer with nylon 6, maximum impact performance was obtained by addition of about 10 wt% of the modifier and the impact strength was further enhanced by increasing the acrylic acid content from 3.5 to 6%. However, blends prepared using the salt form ionomer (Sur-lyn 9950-Zn salt) instead of the acid, led to the highest impact strength, with the least reduction in tensile... 

Table 10.3 Properties of polyurethane/acrylic IPNs compared with blends and homopolymers...

Acrylic Polymerization Model. Acrylic polymers are known to have excellent weathering and functional properties as binders for coatings, and they are widely used in the coatings as well as many other industries. To obtain the desirable property/cost balance, random copolymers instead of blends of homopolymers are frequently used. 

Properties of plastic3 LDPE LLDP E HDPE PP PVC (flexible ) PS ABS Poly acrylic (glazing) Polycarbonat e (glazing) Epoxy (minera 1 filled) Acetal homopolym er... 

The butadiene and butadiene-acrylic monomer systems polymerize when irradiated on PVC or vinyl chloride copolymer latex. The structure of the polymer obtained may be grafted if it can be proved that the copolymer properties are different from the blend properties. To elucidate the structure we studied a copolymer obtained by polymerizing butadiene-acrylonitrile on a PVC homopolymer lattice. Owing to practical reasons and to exclude the secondary effect of catalytic residues we used y radiation. However, we shall observe in a particular case the properties of peroxide-initiated graft copolymer. 

The acrylic plastics use the term acryl such as polymethyl methacrylate (PMMA), polyacrylic acid, polymethacrytic acid, poly-R acrylate, poly-R methacrylate, polymethylacrylate, polyethylmethacrylate, and cyanoacrylate plastics. PMMA is the major and most important homopolymer in the series of acrylics with a sufficient high glass transition temperature to form useful products. Repeat units of the other types are used. Ethylacrylate repeat units form the major component in acrylate rubbers. PMMAs have high optical clarity, excellent weatherability, very broad color range, and hardest surface of any untreated thermoplastic. Chemical, thermal and impact properties are good to fair. Acrylics will fail in a brittle manner, independent of the temperature. They will suffer crazing when loaded at stress about halfway to the failure level. This effect is enhanced by the presence of solvents. 

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