【豆丁推荐】-》ACR中壳层PMMA分子量对PVC-ACR共混物性能的影响

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摘要：聚丙烯酸酯树脂（ACR ）作为聚氯乙烯增韧改性剂的研究日臻成熟，在以前的报道
中，无论是同氯乙烯进行化学接枝改性还是与聚氯乙烯进行物理共混改性[1-3]，ACR 均是一种良好的增韧剂，并且国内外已有商品树脂可供使用。

在制备ACR 树脂时，通常采用PMMA 为Fig.1 Effect of content of the n-octyl mercaptan on the
molecular weight of PMMA in ACR
Fig.2 Relationship of molecular weight of PMMA on the mechanical properties of PVC-ACR Blends
通常纯聚氯乙烯树脂的缺口冲击强度在2～4KJ/m 2之间，拉伸强度约为57MPa 左右。

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从图2中数据可以看出，共混树脂的冲击强度较纯PVC树脂均有提高（2倍以上），拉伸强
度稍有下降。

ACR中壳层聚合物分子量在一定范围内（12×104～50×104）对共混树脂性能
的影响不很明显，只有当其分子量很低时（＜12×104），共混树脂的韧性发生较大改善。

尤
其当分子量降低到6.32×104时，共混树脂的冲击韧性提高约9倍左右（3.4 KJ/m2→38KJ/m2）。

分析原因，可能是因为ACR壳层PMMA作为核层与PVC基体之间的相容剂，分子量的大
小对其相容性作用有一定影响。

当分子量减小到某一范围时，PMMA分子链在共混树脂加
工过程中，与较高分子量PMMA相比更容易与基体PVC树脂渗透，但是又不会完全相容，
这样有利于ACR核层橡胶相能够充分发挥增韧效果。

为了考察ACR壳层分子量对共混树
脂影响的最低值，我们试图继续增加ACR乳液聚合反应壳层单体中正辛基硫醇的含量，但
是当正辛基硫醇含量过高时（＞10wt%），PMMA分子量过低，不能有效的包覆核层橡胶相，
因此不能制备流动性良好的粉末树脂。

因此，从制备具有一定流动性的改性树脂方面考虑，
ACR壳层聚合物的分子量不能无限降低。

参考文献：
[1]Mingwang Pan, Liucheng Zhang, Linzhan Wan, Ruiqiang Guo. Preparation and
characterization of composite resin by vinyl chloride grafted onto poly(BA-EHA)/poly (MMA-St), Polymer, 2003, 44: 7121-7129.
[2] Liucheng Zhang, Mingwang Pan, Jian Zhang. n-Butyl acrylate based latex interpenetrating
polymer networks used as processing modifiers and impact modifiers of poly(vinyl chloride),
Journal of Applied Polymer Science, 2004, 91,1168-1173.
[3] Mingwang Pan, Liucheng Zhang, Jinfeng Yuan. Xudong Shi. Rheological behavior and
thermal properties of poly(butyl acrylate-co-2-ethylhexyl acrylate) grafted vinyl chloride resin.
Journal of Applied Polymer Science, 2005, 95(2): 419-426.
[4] D. J. Walsh and J. G. Mckeown Compatibility of polyacrylates and polymethacrylates with
poly(vinyl chloride):patibility and temperature variation Polymer,1980,V ol.21,1330-1334.
[5] D. J. Walsh and G. L. Cheng The miscibility of polyacrylates and polymethacrylates with
PVC: An interpretation of the heats of mixing of oligomers Polymer,1984,V ol.25,499-502.
Effect of molecular weight of PMMA on the mechanical properties of
PVC-ACR Blends
Jinfeng Yuan, Mingwang Pan, Fengxiang Ding, Liucheng Zhang*
Insititute of Polymer Science&Engineering, Hebei University of Technology, Tianjin
300130, China
Polyvinyl chloride(PVC) were toughened with polybutyl acrylate/polymethyl methacrylate
core/shell impact modifier resin(ACR). It was well known that PMMA was compatible with PVC. n-Octyl Mercaptan was used as chain transfer agent to regulate the molecular weight of
PMMA. The influence of molecular weight of PMMA on the mechanical properties of PVC/ACR Blends was investigated. PVC/ACR blends with different PMMA molecular weight were prepared on a two-roll mill. The blend containing lower molecular weight of PMMA exhibits better notched impact strength than that of the others.
Keywords: Blending modification of PVC, adjusting molecular weight, chain transfer agent, ACR resin.。